grafana/pkg/services/ngalert/state/manager_private_test.go

package state

import (
	"context"
	"errors"
	"fmt"
	"math/rand"
	"sort"
	"testing"
	"time"

	"github.com/benbjohnson/clock"
	"github.com/google/go-cmp/cmp"
	"github.com/google/go-cmp/cmp/cmpopts"
	"github.com/grafana/grafana-plugin-sdk-go/data"
	"github.com/prometheus/client_golang/prometheus"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	"github.com/grafana/grafana/pkg/expr"
	"github.com/grafana/grafana/pkg/infra/log"
	"github.com/grafana/grafana/pkg/infra/tracing"
	"github.com/grafana/grafana/pkg/services/ngalert/eval"
	"github.com/grafana/grafana/pkg/services/ngalert/metrics"
	ngmodels "github.com/grafana/grafana/pkg/services/ngalert/models"
)

// Not for parallel tests.
type CountingImageService struct {
	Called int
}

func (c *CountingImageService) NewImage(_ context.Context, _ *ngmodels.AlertRule) (*ngmodels.Image, error) {
	c.Called += 1
	return &ngmodels.Image{
		Token: fmt.Sprint(rand.Int()),
	}, nil
}

func TestStateIsStale(t *testing.T) {
	now := time.Now()
	intervalSeconds := rand.Int63n(10) + 5

	testCases := []struct {
		name           string
		lastEvaluation time.Time
		expectedResult bool
	}{
		{
			name:           "false if last evaluation is now",
			lastEvaluation: now,
			expectedResult: false,
		},
		{
			name:           "false if last evaluation is 1 interval before now",
			lastEvaluation: now.Add(-time.Duration(intervalSeconds)),
			expectedResult: false,
		},
		{
			name:           "false if last evaluation is little less than 2 interval before now",
			lastEvaluation: now.Add(-time.Duration(intervalSeconds) * time.Second * 2).Add(100 * time.Millisecond),
			expectedResult: false,
		},
		{
			name:           "true if last evaluation is 2 intervals from now",
			lastEvaluation: now.Add(-time.Duration(intervalSeconds) * time.Second * 2),
			expectedResult: true,
		},
		{
			name:           "true if last evaluation is 3 intervals from now",
			lastEvaluation: now.Add(-time.Duration(intervalSeconds) * time.Second * 3),
			expectedResult: true,
		},
	}
	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			require.Equal(t, tc.expectedResult, stateIsStale(now, tc.lastEvaluation, intervalSeconds))
		})
	}
}

// TestProcessEvalResults_StateTransitions tests how state.Manager's ProcessEvalResults processes results and creates or changes states.
// In other words, it tests the state transition.
//
// The tests use a micro-framework that has the following features:
//  1. It uses a base rule definition and allows each test case mutate its copy.
//  2. Expected State definition omits several fields which are patched before assertion
//     if they are not specified explicitly (see function "patchState" for patched fields).
//     This allows specifications to be more condense and mention only important fields.
//  3. Expected State definition uses some shortcut functions to make the specification more clear.
//     Expected labels are populated from a labels map where keys = description of what labels included in its values.
//     This allows us to specify the list of labels expected to be in the state in one line, e.g. "system + rule + labels1"
//     Evaluations are populated using function `newEvaluation` that pre-set all important fields.
//  4. Each test case can contain multiple consecutive evaluations at different times with assertions at every interval.
//     The framework offers variables t1, t2, t3 and function tN(n) that provide timestamps of different evaluations.
//  5. NoData and Error tests require assertions for all possible execution options for the same input.
//
// # Naming convention for tests cases.
//
// The tests are formatted to the input characteristics, such as rule definition,
// result format (multi- or single- dimensional) and at which times the assertions are defined.
//
// <time>[(<labelSet>:)<eval.State>] (and <rule_modifications>) at <asserted_time>
//
//	Where:
//	  - <time> can be t1, t2 or t3, i.e. timestamp of evaluation.
//	  - <labelSet> indicates the label set of the normal result. It can be 1,2,3 which corresponds to labels1, labels2 and labels3, or {} for results without labels.
//	    In the case of NoData or Error labelSet is omitted
//	  - <rule_modifications> rule modifications.
//	  - <asserted_time> at which time intervals the test executes assertions. Can be t1,t2 or t3.
//
// For example:
//
//	t1[1:normal] t2[1:alerting] and 'for'=2 at t2
//	t1[{}:alerting] t2[{}:normal] t3[NoData] at t2,t3
//
//nolint:gocyclo
func TestProcessEvalResults_StateTransitions(t *testing.T) {
	evaluationDuration := 10 * time.Millisecond
	evaluationInterval := 10 * time.Second

	tN := func(n int) time.Time {
		return time.Time{}.Add(time.Duration(n) * evaluationInterval)
	}
	t1 := tN(1)
	t2 := tN(2)
	t3 := tN(3)

	baseRule := &ngmodels.AlertRule{
		OrgID: 1,
		Title: "test_title",
		UID:   "test_alert_rule_uid",
		Data: []ngmodels.AlertQuery{{
			RefID:         "A",
			DatasourceUID: "datasource_uid_1",
		}, {
			RefID:         "B",
			DatasourceUID: expr.DatasourceType,
		}},
		NamespaceUID:    "test_namespace_uid",
		Annotations:     map[string]string{"annotation": "test"},
		Labels:          map[string]string{"label": "test"},
		IntervalSeconds: int64(evaluationInterval.Seconds()),
		NoDataState:     ngmodels.NoData,
		ExecErrState:    ngmodels.ErrorErrState,
	}

	baseRuleWith := func(mutators ...ngmodels.AlertRuleMutator) *ngmodels.AlertRule {
		r := ngmodels.CopyRule(baseRule)
		for _, mutator := range mutators {
			mutator(r)
		}
		return r
	}

	newEvaluation := func(evalTime time.Time, evalState eval.State) Evaluation {
		return Evaluation{
			EvaluationTime:  evalTime,
			EvaluationState: evalState,
			Values:          make(map[string]*float64),
		}
	}

	newResult := func(mutators ...eval.ResultMutator) eval.Result {
		r := eval.Result{
			State:              eval.Normal,
			EvaluationDuration: evaluationDuration,
		}
		for _, mutator := range mutators {
			mutator(&r)
		}
		return r
	}

	genericError := errors.New("test-error")
	datasourceError := expr.MakeQueryError("A", "datasource_uid_1", errors.New("this is an error"))
	expectedDatasourceErrorLabels := data.Labels{
		"datasource_uid": "datasource_uid_1",
		"ref_id":         "A",
	}

	labels1 := data.Labels{
		"instance_label": "test-1",
	}
	labels2 := data.Labels{
		"instance_label": "test-2",
	}
	labels3 := data.Labels{
		"instance_label": "test-3",
	}
	systemLabels := data.Labels{
		"system": "owned",
	}
	noDataLabels := data.Labels{
		"datasource_uid": "1",
		"ref_id":         "A",
	}

	labels := map[string]data.Labels{
		"system + rule":                    mergeLabels(baseRule.Labels, systemLabels),
		"system + rule + labels1":          mergeLabels(mergeLabels(labels1, baseRule.Labels), systemLabels),
		"system + rule + labels2":          mergeLabels(mergeLabels(labels2, baseRule.Labels), systemLabels),
		"system + rule + labels3":          mergeLabels(mergeLabels(labels3, baseRule.Labels), systemLabels),
		"system + rule + no-data":          mergeLabels(mergeLabels(noDataLabels, baseRule.Labels), systemLabels),
		"system + rule + datasource-error": mergeLabels(mergeLabels(expectedDatasourceErrorLabels, baseRule.Labels), systemLabels),
	}

	resultFingerprints := map[string]data.Fingerprint{
		"system + rule":                    data.Labels{}.Fingerprint(),
		"system + rule + labels1":          labels1.Fingerprint(),
		"system + rule + labels2":          labels2.Fingerprint(),
		"system + rule + labels3":          labels3.Fingerprint(),
		"system + rule + no-data":          noDataLabels.Fingerprint(),
		"system + rule + datasource-error": data.Labels{}.Fingerprint(),
	}

	patchState := func(r *ngmodels.AlertRule, s *State) {
		// patch all optional fields of the expected state
		setCacheID(s)
		if s.AlertRuleUID == "" {
			s.AlertRuleUID = r.UID
		}
		if s.OrgID == 0 {
			s.OrgID = r.OrgID
		}
		if s.Annotations == nil {
			s.Annotations = r.Annotations
		}
		if s.EvaluationDuration == 0 {
			s.EvaluationDuration = evaluationDuration
		}
		if s.Values == nil {
			s.Values = make(map[string]float64)
		}
		if s.ResultFingerprint == data.Fingerprint(0) {
			for key, set := range labels {
				if set.Fingerprint() == s.Labels.Fingerprint() {
					s.ResultFingerprint = resultFingerprints[key]
					break
				}
			}
		}
	}

	executeTest := func(t *testing.T, alertRule *ngmodels.AlertRule, resultsAtTime map[time.Time]eval.Results, expectedTransitionsAtTime map[time.Time][]StateTransition, applyNoDataErrorToAllStates bool) {
		clk := clock.NewMock()

		testMetrics := metrics.NewNGAlert(prometheus.NewPedanticRegistry()).GetStateMetrics()
		cfg := ManagerCfg{
			Metrics:       testMetrics,
			Tracer:        tracing.InitializeTracerForTest(),
			Log:           log.New("ngalert.state.manager"),
			ExternalURL:   nil,
			InstanceStore: &FakeInstanceStore{},
			Images:        &NotAvailableImageService{},
			Clock:         clk,
			Historian:     &FakeHistorian{},

			ApplyNoDataAndErrorToAllStates: applyNoDataErrorToAllStates,
		}
		st := NewManager(cfg, NewNoopPersister())

		tss := make([]time.Time, 0, len(resultsAtTime))
		for ts, results := range resultsAtTime {
			for i := range results {
				results[i].EvaluatedAt = ts
			}
			tss = append(tss, ts)
		}
		sort.Slice(tss, func(i, j int) bool {
			return tss[i].Before(tss[j])
		})

		for _, ts := range tss {
			results := resultsAtTime[ts]
			clk.Set(ts)
			actual := st.ProcessEvalResults(context.Background(), ts, alertRule, results, systemLabels)

			expectedTransitions, ok := expectedTransitionsAtTime[ts]
			if !ok { // skip if nothing to assert
				continue
			}
			expectedTransitionsMap := make(map[string]StateTransition, len(expectedTransitions))
			for i := range expectedTransitions {
				patchState(alertRule, expectedTransitions[i].State)
				expectedTransitionsMap[expectedTransitions[i].CacheID] = expectedTransitions[i]
			}

			tn := ts.Sub(t1)/evaluationInterval + 1
			for _, transition := range actual {
				expected, ok := expectedTransitionsMap[transition.CacheID]
				if !ok {
					assert.Failf(t, fmt.Sprintf("transition is not expected at time [t%d]", tn), "CacheID: %s.\nTransition: %s->%s", transition.CacheID, transition.PreviousFormatted(), transition.Formatted())
				}
				delete(expectedTransitionsMap, transition.CacheID)
				if !assert.ObjectsAreEqual(expected, transition) {
					assert.Failf(t, fmt.Sprintf("expected and actual transitions at time [t%d] are not equal", tn), "CacheID: %s\nDiff: %s", transition.CacheID, cmp.Diff(expected, transition, cmpopts.EquateErrors()))
				}
			}
			if len(expectedTransitionsMap) > 0 {
				vals := make([]string, 0, len(expectedTransitionsMap))
				for _, s := range expectedTransitionsMap {
					vals = append(vals, s.CacheID)
				}
				assert.Failf(t, fmt.Sprintf("some expected states do not exist at time [t%d]", tn), "States: %v", vals)
			}
		}
	}

	type testCase struct {
		desc                string
		alertRule           *ngmodels.AlertRule
		results             map[time.Time]eval.Results
		expectedTransitions map[time.Time][]StateTransition
	}

	testCases := []testCase{
		{
			desc:      "t1[1:normal,2:normal] at t1",
			alertRule: baseRule,
			results: map[time.Time]eval.Results{
				t1: {
					newResult(eval.WithState(eval.Normal), eval.WithLabels(labels1)),
					newResult(eval.WithState(eval.Normal), eval.WithLabels(labels2)),
				},
			},
			expectedTransitions: map[time.Time][]StateTransition{
				t1: {
					{
						PreviousState: eval.Normal,
						State: &State{
							Labels: labels["system + rule + labels1"],
							State:  eval.Normal,
							Results: []Evaluation{
								newEvaluation(t1, eval.Normal),
							},
							StartsAt:           t1,
							EndsAt:             t1,
							LastEvaluationTime: t1,
						},
					},
					{
						PreviousState: eval.Normal,
						State: &State{
							Labels: labels["system + rule + labels2"],
							State:  eval.Normal,
							Results: []Evaluation{
								newEvaluation(t1, eval.Normal),
							},
							StartsAt:           t1,
							EndsAt:             t1,
							LastEvaluationTime: t1,
						},
					},
				},
			},
		},
		{
			desc:      "t1[1:alerting,2:normal] at t1",
			alertRule: baseRule,
			results: map[time.Time]eval.Results{
				t1: {
					newResult(eval.WithState(eval.Alerting), eval.WithLabels(labels1)),
					newResult(eval.WithState(eval.Normal), eval.WithLabels(labels2)),
				},
			},
			expectedTransitions: map[time.Time][]StateTransition{
				t1: {
					{
						PreviousState: eval.Normal,
						State: &State{
							Labels: labels["system + rule + labels1"],
							State:  eval.Alerting,
							Results: []Evaluation{
								newEvaluation(t1, eval.Alerting),
							},
							StartsAt:           t1,
							EndsAt:             t1.Add(ResendDelay * 4),
							LastEvaluationTime: t1,
						},
					},
					{
						PreviousState: eval.Normal,
						State: &State{
							Labels: labels["system + rule + labels2"],
							State:  eval.Normal,
							Results: []Evaluation{
								newEvaluation(t1, eval.Normal),
							},
							StartsAt:           t1,
							EndsAt:             t1,
							LastEvaluationTime: t1,
						},
					},
				},
			},
		},
		{
			desc:      "t1[1:alerting,2:normal] and 'for'>0 at t1",
			alertRule: baseRuleWith(ngmodels.WithForNTimes(3)),
			results: map[time.Time]eval.Results{
				t1: {
					newResult(eval.WithState(eval.Alerting), eval.WithLabels(labels1)),
					newResult(eval.WithState(eval.Normal), eval.WithLabels(labels2)),
				},
			},
			expectedTransitions: map[time.Time][]StateTransition{
				t1: {
					{
						PreviousState: eval.Normal,
						State: &State{
							Labels: labels["system + rule + labels1"],
							State:  eval.Pending,
							Results: []Evaluation{
								newEvaluation(t1, eval.Alerting),
							},
							StartsAt:           t1,
							EndsAt:             t1.Add(ResendDelay * 4),
							LastEvaluationTime: t1,
						},
					},
					{
						PreviousState: eval.Normal,
						State: &State{
							Labels: labels["system + rule + labels2"],
							State:  eval.Normal,
							Results: []Evaluation{
								newEvaluation(t1, eval.Normal),
							},
							StartsAt:           t1,
							EndsAt:             t1,
							LastEvaluationTime: t1,
						},
					},
				},
			},
		},
		{
			desc:      "t1[1:normal,2:normal] t2[1:alerting,2:normal] at t2",
			alertRule: baseRule,
			results: map[time.Time]eval.Results{
				t1: {
					newResult(eval.WithState(eval.Normal), eval.WithLabels(labels1)),
					newResult(eval.WithState(eval.Normal), eval.WithLabels(labels2)),
				},
				t2: {
					newResult(eval.WithState(eval.Alerting), eval.WithLabels(labels1)),
					newResult(eval.WithState(eval.Normal), eval.WithLabels(labels2)),
				},
			},
			expectedTransitions: map[time.Time][]StateTransition{
				t2: {
					{
						PreviousState: eval.Normal,
						State: &State{
							Labels: labels["system + rule + labels1"],
							State:  eval.Alerting,
							Results: []Evaluation{
								newEvaluation(t1, eval.Normal),
								newEvaluation(t2, eval.Alerting),
							},
							StartsAt:           t2,
							EndsAt:             t2.Add(ResendDelay * 4),
							LastEvaluationTime: t2,
						},
					},
					{
						PreviousState: eval.Normal,
						State: &State{
							Labels: labels["system + rule + labels2"],
							State:  eval.Normal,
							Results: []Evaluation{
								newEvaluation(t1, eval.Normal),
								newEvaluation(t2, eval.Normal),
							},
							StartsAt:           t1,
							EndsAt:             t1,
							LastEvaluationTime: t2,
						},
					},
				},
			},
		},
		{
			desc:      "t1[1:alerting] t2[1:alerting] t3[1:alerting] and 'for'=2 at t1,t2,t3",
			alertRule: baseRuleWith(ngmodels.WithForNTimes(2)),
			results: map[time.Time]eval.Results{
				t1: {
					newResult(eval.WithState(eval.Alerting), eval.WithLabels(labels1)),
				},
				t2: {
					newResult(eval.WithState(eval.Alerting), eval.WithLabels(labels1)),
				},
				t3: {
					newResult(eval.WithState(eval.Alerting), eval.WithLabels(labels1)),
				},
			},
			expectedTransitions: map[time.Time][]StateTransition{
				t1: {
					{
						PreviousState: eval.Normal,
						State: &State{
							Labels: labels["system + rule + labels1"],
							State:  eval.Pending,
							Results: []Evaluation{
								newEvaluation(t1, eval.Alerting),
							},
							StartsAt:           t1,
							EndsAt:             t1.Add(ResendDelay * 4),
							LastEvaluationTime: t1,
						},
					},
				},
				t2: {
					{
						PreviousState: eval.Pending,
						State: &State{
							Labels: labels["system + rule + labels1"],
							State:  eval.Pending,
							Results: []Evaluation{
								newEvaluation(t1, eval.Alerting),
								newEvaluation(t2, eval.Alerting),
							},
							StartsAt:           t1,
							EndsAt:             t1.Add(ResendDelay * 4), // TODO probably it should be t1 (semantic of Normal)?
							LastEvaluationTime: t2,
						},
					},
				},
				t3: {
					{
						PreviousState: eval.Pending,
						State: &State{
							Labels: labels["system + rule + labels1"],
							State:  eval.Alerting,
							Results: []Evaluation{
								newEvaluation(t2, eval.Alerting),
								newEvaluation(t3, eval.Alerting),
							},
							StartsAt:           t3,
							EndsAt:             t3.Add(ResendDelay * 4),
							LastEvaluationTime: t3,
						},
					},
				},
			},
		},
		{
			desc:      "t1[1:alerting], t2[1:normal] and 'for'=2 at t2",
			alertRule: baseRuleWith(ngmodels.WithForNTimes(2)),
			results: map[time.Time]eval.Results{
				t1: {
					newResult(eval.WithState(eval.Alerting), eval.WithLabels(labels1)),
				},
				t2: {
					newResult(eval.WithState(eval.Normal), eval.WithLabels(labels1)),
				},
			},
			expectedTransitions: map[time.Time][]StateTransition{
				t2: {
					{
						PreviousState: eval.Pending,
						State: &State{
							Labels: labels["system + rule + labels1"],
							State:  eval.Normal,
							Results: []Evaluation{
								newEvaluation(t1, eval.Alerting),
								newEvaluation(t2, eval.Normal),
							},
							StartsAt:           t2,
							EndsAt:             t2,
							LastEvaluationTime: t2,
						},
					},
				},
			},
		},
		{
			desc:      "t1:[1:alerting] t2[1:normal] at t2",
			alertRule: baseRule,
			results: map[time.Time]eval.Results{
				t1: {
					newResult(eval.WithState(eval.Alerting), eval.WithLabels(labels1)),
				},
				t2: {
					newResult(eval.WithState(eval.Normal), eval.WithLabels(labels1)),
				},
			},
			expectedTransitions: map[time.Time][]StateTransition{
				t2: {{
					PreviousState: eval.Alerting,
					State: &State{
						Labels: labels["system + rule + labels1"],
						State:  eval.Normal,
						Results: []Evaluation{
							newEvaluation(t1, eval.Alerting),
							newEvaluation(t2, eval.Normal),
						},
						StartsAt:           t2,
						EndsAt:             t2,
						LastEvaluationTime: t2,
						Resolved:           true,
					},
				},
				},
			},
		},
		{
			desc:      "t1[1:normal,2:alerting,3:normal] t2[3:normal] t3[3:normal] at t2,t3",
			alertRule: baseRule,
			results: map[time.Time]eval.Results{
				t1: {
					newResult(eval.WithState(eval.Normal), eval.WithLabels(labels1)),
					newResult(eval.WithState(eval.Alerting), eval.WithLabels(labels2)),
					newResult(eval.WithState(eval.Normal), eval.WithLabels(labels3)),
				},
				t2: {
					newResult(eval.WithState(eval.Normal), eval.WithLabels(labels3)),
				},
				t3: {
					newResult(eval.WithState(eval.Normal), eval.WithLabels(labels3)),
				},
			},
			expectedTransitions: map[time.Time][]StateTransition{
				t2: {
					{
						PreviousState: eval.Normal,
						State: &State{
							Labels: labels["system + rule + labels3"],
							State:  eval.Normal,
							Results: []Evaluation{
								newEvaluation(t1, eval.Normal),
								newEvaluation(t2, eval.Normal),
							},
							StartsAt:           t1,
							EndsAt:             t1,
							LastEvaluationTime: t2,
						},
					},
				},
				t3: {
					{
						PreviousState: eval.Normal,
						State: &State{
							Labels:      labels["system + rule + labels1"],
							State:       eval.Normal,
							StateReason: ngmodels.StateReasonMissingSeries,
							Results: []Evaluation{
								newEvaluation(t1, eval.Normal),
							},
							StartsAt:           t1,
							EndsAt:             t3,
							LastEvaluationTime: t3,
						},
					},
					{
						PreviousState: eval.Alerting,
						State: &State{
							Labels:      labels["system + rule + labels2"],
							State:       eval.Normal,
							StateReason: ngmodels.StateReasonMissingSeries,
							Results: []Evaluation{
								newEvaluation(t1, eval.Alerting),
							},
							StartsAt:           t1,
							EndsAt:             t3,
							LastEvaluationTime: t3,
							Resolved:           true,
						},
					},
					{
						PreviousState: eval.Normal,
						State: &State{
							Labels: labels["system + rule + labels3"],
							State:  eval.Normal,
							Results: []Evaluation{
								newEvaluation(t1, eval.Normal),
								newEvaluation(t2, eval.Normal),
								newEvaluation(t3, eval.Normal),
							},
							StartsAt:           t1,
							EndsAt:             t1,
							LastEvaluationTime: t3,
						},
					},
				},
			},
		},
		{
			desc:      "t1[{}:normal] at t1",
			alertRule: baseRule,
			results: map[time.Time]eval.Results{
				t1: {
					newResult(eval.WithState(eval.Normal)),
				},
			},
			expectedTransitions: map[time.Time][]StateTransition{
				t1: {
					{
						PreviousState: eval.Normal,
						State: &State{
							Labels: labels["system + rule"],
							State:  eval.Normal,
							Results: []Evaluation{
								newEvaluation(t1, eval.Normal),
							},
							StartsAt:           t1,
							EndsAt:             t1,
							LastEvaluationTime: t1,
						},
					},
				},
			},
		},
		{
			desc:      "t1[{}:alerting] at t1",
			alertRule: baseRule,
			results: map[time.Time]eval.Results{
				t1: {
					newResult(eval.WithState(eval.Alerting)),
				},
			},
			expectedTransitions: map[time.Time][]StateTransition{
				t1: {
					{
						PreviousState: eval.Normal,
						State: &State{
							Labels: labels["system + rule"],
							State:  eval.Alerting,
							Results: []Evaluation{
								newEvaluation(t1, eval.Alerting),
							},
							StartsAt:           t1,
							EndsAt:             t1.Add(ResendDelay * 4),
							LastEvaluationTime: t1,
						},
					},
				},
			},
		},
		{
			desc:      "t1[{}:alerting] and 'for'>0  at t1",
			alertRule: baseRuleWith(ngmodels.WithForNTimes(3)),
			results: map[time.Time]eval.Results{
				t1: {
					newResult(eval.WithState(eval.Alerting)),
				},
			},
			expectedTransitions: map[time.Time][]StateTransition{
				t1: {
					{
						PreviousState: eval.Normal,
						State: &State{
							Labels: labels["system + rule"],
							State:  eval.Pending,
							Results: []Evaluation{
								newEvaluation(t1, eval.Alerting),
							},
							StartsAt:           t1,
							EndsAt:             t1.Add(ResendDelay * 4),
							LastEvaluationTime: t1,
						},
					},
				},
			},
		},
		{
			desc:      "t1[{}:normal] t2[{}:alerting] at t2",
			alertRule: baseRule,
			results: map[time.Time]eval.Results{
				t1: {
					newResult(eval.WithState(eval.Normal)),
				},
				t2: {
					newResult(eval.WithState(eval.Alerting)),
				},
			},
			expectedTransitions: map[time.Time][]StateTransition{
				t2: {
					{
						PreviousState: eval.Normal,
						State: &State{
							Labels: labels["system + rule"],
							State:  eval.Alerting,
							Results: []Evaluation{
								newEvaluation(t1, eval.Normal),
								newEvaluation(t2, eval.Alerting),
							},
							StartsAt:           t2,
							EndsAt:             t2.Add(ResendDelay * 4),
							LastEvaluationTime: t2,
						},
					},
				},
			},
		},
	}

	for _, tc := range testCases {
		t.Run(tc.desc, func(t *testing.T) {
			t.Run("applyNoDataErrorToAllStates=true", func(t *testing.T) {
				executeTest(t, tc.alertRule, tc.results, tc.expectedTransitions, true)
			})
			t.Run("applyNoDataErrorToAllStates=false", func(t *testing.T) {
				executeTest(t, tc.alertRule, tc.results, tc.expectedTransitions, false)
			})
		})
	}

	t.Run("no-data", func(t *testing.T) {
		rules := map[ngmodels.NoDataState]*ngmodels.AlertRule{
			ngmodels.NoData:   baseRuleWith(ngmodels.WithNoDataExecAs(ngmodels.NoData)),
			ngmodels.Alerting: baseRuleWith(ngmodels.WithNoDataExecAs(ngmodels.Alerting)),
			ngmodels.OK:       baseRuleWith(ngmodels.WithNoDataExecAs(ngmodels.OK)),
			ngmodels.KeepLast: baseRuleWith(ngmodels.WithNoDataExecAs(ngmodels.KeepLast)),
		}

		type noDataTestCase struct {
			desc                string
			ruleMutators        []ngmodels.AlertRuleMutator
			results             map[time.Time]eval.Results
			expectedTransitions map[ngmodels.NoDataState]map[time.Time][]StateTransition

			expectedTransitionsApplyNoDataErrorToAllStates map[ngmodels.NoDataState]map[time.Time][]StateTransition
		}

		executeForEachRule := func(t *testing.T, tc noDataTestCase) {
			t.Helper()
			for stateExec, rule := range rules {
				r := rule
				if len(tc.ruleMutators) > 0 {
					r = ngmodels.CopyRule(r)
					for _, mutateRule := range tc.ruleMutators {
						mutateRule(r)
					}
				}
				t.Run(fmt.Sprintf("execute as %s", stateExec), func(t *testing.T) {
					expectedTransitions, ok := tc.expectedTransitionsApplyNoDataErrorToAllStates[stateExec]
					overridden := "[*]"
					if !ok {
						expectedTransitions, ok = tc.expectedTransitions[stateExec]
						overridden = ""
					}
					if !ok {
						require.Fail(t, "no expected state transitions")
					}
					t.Run("applyNoDataErrorToAllStates=true"+overridden, func(t *testing.T) {
						executeTest(t, r, tc.results, expectedTransitions, true)
					})
					t.Run("applyNoDataErrorToAllStates=false", func(t *testing.T) {
						expectedTransitions, ok := tc.expectedTransitions[stateExec]
						if !ok {
							require.Fail(t, "no expected state transitions")
						}
						executeTest(t, r, tc.results, expectedTransitions, false)
					})
				})
			}
		}

		testCases := []noDataTestCase{
			{
				desc: "t1[NoData] at t1",
				results: map[time.Time]eval.Results{
					t1: {
						newResult(eval.WithState(eval.NoData), eval.WithLabels(noDataLabels)),
					},
				},
				expectedTransitions: map[ngmodels.NoDataState]map[time.Time][]StateTransition{
					ngmodels.NoData: {
						t1: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels: labels["system + rule + no-data"],
									State:  eval.NoData,
									Results: []Evaluation{
										newEvaluation(t1, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t1.Add(ResendDelay * 4),
									LastEvaluationTime: t1,
								},
							},
						},
					},
					ngmodels.Alerting: {
						t1: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + no-data"],
									State:       eval.Alerting,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t1, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t1.Add(ResendDelay * 4),
									LastEvaluationTime: t1,
								},
							},
						},
					},
					ngmodels.OK: {
						t1: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + no-data"],
									State:       eval.Normal,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t1, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t1,
									LastEvaluationTime: t1,
								},
							},
						},
					},
					ngmodels.KeepLast: {
						t1: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + no-data"],
									State:       eval.Normal,
									StateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t1, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t1,
									LastEvaluationTime: t1,
								},
							},
						},
					},
				},
			},
			{
				desc: "t1[1:normal] t2[NoData] at t2",
				results: map[time.Time]eval.Results{
					t1: {
						newResult(eval.WithState(eval.Normal), eval.WithLabels(labels1)),
					},
					t2: {
						newResult(eval.WithState(eval.NoData), eval.WithLabels(noDataLabels)),
					},
				},
				expectedTransitions: map[ngmodels.NoDataState]map[time.Time][]StateTransition{
					ngmodels.NoData: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels: labels["system + rule + no-data"],
									State:  eval.NoData,
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
					},
					ngmodels.Alerting: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + no-data"],
									State:       eval.Alerting,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
					},
					ngmodels.OK: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + no-data"],
									State:       eval.Normal,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t2,
								},
							},
						},
					},
					ngmodels.KeepLast: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + no-data"],
									State:       eval.Normal,
									StateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t2,
								},
							},
						},
					},
				},
				expectedTransitionsApplyNoDataErrorToAllStates: map[ngmodels.NoDataState]map[time.Time][]StateTransition{
					ngmodels.Alerting: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Alerting,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
					},
					ngmodels.OK: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Normal,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t1,
									LastEvaluationTime: t2,
								},
							},
						},
					},
					ngmodels.KeepLast: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Normal,
									StateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t1,
									LastEvaluationTime: t2,
								},
							},
						},
					},
				},
			},
			{
				desc: "t1[1:normal,2:alerting] t2[NoData] t3[NoData] at t2,t3",
				results: map[time.Time]eval.Results{
					t1: {
						newResult(eval.WithState(eval.Normal), eval.WithLabels(labels1)),
						newResult(eval.WithState(eval.Alerting), eval.WithLabels(labels2)),
					},
					t2: {
						newResult(eval.WithState(eval.NoData), eval.WithLabels(noDataLabels)),
					},
					t3: {
						newResult(eval.WithState(eval.NoData), eval.WithLabels(noDataLabels)),
					},
				},
				expectedTransitions: map[ngmodels.NoDataState]map[time.Time][]StateTransition{
					ngmodels.NoData: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels: labels["system + rule + no-data"],
									State:  eval.NoData,
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
						t3: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState: eval.Alerting,
								State: &State{
									Labels:      labels["system + rule + labels2"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
									Resolved:           true,
								},
							},
							{
								PreviousState: eval.NoData,
								State: &State{
									Labels: labels["system + rule + no-data"],
									State:  eval.NoData,
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.Alerting: {
						t3: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState: eval.Alerting,
								State: &State{
									Labels:      labels["system + rule + labels2"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
									Resolved:           true,
								},
							},
							{
								PreviousState:       eval.Alerting,
								PreviousStateReason: eval.NoData.String(),
								State: &State{
									Labels:      labels["system + rule + no-data"],
									State:       eval.Alerting,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.OK: {
						t3: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState: eval.Alerting,
								State: &State{
									Labels:      labels["system + rule + labels2"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
									Resolved:           true,
								},
							},
							{
								PreviousState:       eval.Normal,
								PreviousStateReason: eval.NoData.String(),
								State: &State{
									Labels:      labels["system + rule + no-data"],
									State:       eval.Normal,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.KeepLast: {
						t3: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState: eval.Alerting,
								State: &State{
									Labels:      labels["system + rule + labels2"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
									Resolved:           true,
								},
							},
							{
								PreviousState:       eval.Normal,
								PreviousStateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
								State: &State{
									Labels:      labels["system + rule + no-data"],
									State:       eval.Normal,
									StateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t3,
								},
							},
						},
					},
				},
				expectedTransitionsApplyNoDataErrorToAllStates: map[ngmodels.NoDataState]map[time.Time][]StateTransition{
					ngmodels.Alerting: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Alerting,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
							{
								PreviousState: eval.Alerting,
								State: &State{
									Labels:      labels["system + rule + labels2"],
									State:       eval.Alerting,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
						t3: {
							{
								PreviousState:       eval.Alerting,
								PreviousStateReason: eval.NoData.String(),
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Alerting,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
										newEvaluation(t2, eval.NoData),
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState:       eval.Alerting,
								PreviousStateReason: eval.NoData.String(),
								State: &State{
									Labels:      labels["system + rule + labels2"],
									State:       eval.Alerting,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
										newEvaluation(t2, eval.NoData),
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.OK: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Normal,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t1,
									LastEvaluationTime: t2,
								},
							},
							{
								PreviousState: eval.Alerting,
								State: &State{
									Labels:      labels["system + rule + labels2"],
									State:       eval.Normal,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t2,
									Resolved:           true,
								},
							},
						},
						t3: {
							{
								PreviousState:       eval.Normal,
								PreviousStateReason: eval.NoData.String(),
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Normal,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
										newEvaluation(t2, eval.NoData),
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t1,
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState:       eval.Normal,
								PreviousStateReason: eval.NoData.String(),
								State: &State{
									Labels:      labels["system + rule + labels2"],
									State:       eval.Normal,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
										newEvaluation(t2, eval.NoData),
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.KeepLast: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Normal,
									StateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t1,
									LastEvaluationTime: t2,
								},
							},
							{
								PreviousState: eval.Alerting,
								State: &State{
									Labels:      labels["system + rule + labels2"],
									State:       eval.Alerting,
									StateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
						t3: {
							{
								PreviousState:       eval.Normal,
								PreviousStateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Normal,
									StateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
										newEvaluation(t2, eval.NoData),
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t1,
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState:       eval.Alerting,
								PreviousStateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
								State: &State{
									Labels:      labels["system + rule + labels2"],
									State:       eval.Alerting,
									StateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
										newEvaluation(t2, eval.NoData),
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
				},
			},
			{
				desc:         "t1[1:normal,2:alerting] t2[NoData] t3[NoData] and 'for'=1 at t2*,t3",
				ruleMutators: []ngmodels.AlertRuleMutator{ngmodels.WithForNTimes(1)},
				results: map[time.Time]eval.Results{
					t1: {
						newResult(eval.WithState(eval.Normal), eval.WithLabels(labels1)),
						newResult(eval.WithState(eval.Alerting), eval.WithLabels(labels2)),
					},
					t2: {
						newResult(eval.WithState(eval.NoData), eval.WithLabels(noDataLabels)),
					},
					t3: {
						newResult(eval.WithState(eval.NoData), eval.WithLabels(noDataLabels)),
					},
				},
				expectedTransitions: map[ngmodels.NoDataState]map[time.Time][]StateTransition{
					ngmodels.NoData: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels: labels["system + rule + no-data"],
									State:  eval.NoData,
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
						t3: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState: eval.Pending,
								State: &State{
									Labels:      labels["system + rule + labels2"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState: eval.NoData,
								State: &State{
									Labels: labels["system + rule + no-data"],
									State:  eval.NoData,
									Results: []Evaluation{
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.Alerting: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + no-data"],
									State:       eval.Pending,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
						t3: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState: eval.Pending,
								State: &State{
									Labels:      labels["system + rule + labels2"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState:       eval.Pending,
								PreviousStateReason: eval.NoData.String(),
								State: &State{
									Labels:      labels["system + rule + no-data"],
									State:       eval.Alerting,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t3,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.OK: {
						t3: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState: eval.Pending,
								State: &State{
									Labels:      labels["system + rule + labels2"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState:       eval.Normal,
								PreviousStateReason: eval.NoData.String(),
								State: &State{
									Labels:      labels["system + rule + no-data"],
									State:       eval.Normal,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.KeepLast: {
						t3: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState: eval.Pending,
								State: &State{
									Labels:      labels["system + rule + labels2"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState:       eval.Normal,
								PreviousStateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
								State: &State{
									Labels:      labels["system + rule + no-data"],
									State:       eval.Normal,
									StateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t3,
								},
							},
						},
					},
				},
				expectedTransitionsApplyNoDataErrorToAllStates: map[ngmodels.NoDataState]map[time.Time][]StateTransition{
					ngmodels.Alerting: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Pending,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
							{
								PreviousState: eval.Pending,
								State: &State{
									Labels:      labels["system + rule + labels2"],
									State:       eval.Alerting,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
						t3: {
							{
								PreviousState:       eval.Pending,
								PreviousStateReason: eval.NoData.String(),
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Alerting,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t3,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState:       eval.Alerting,
								PreviousStateReason: eval.NoData.String(),
								State: &State{
									Labels:      labels["system + rule + labels2"],
									State:       eval.Alerting,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.OK: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Normal,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t1,
									LastEvaluationTime: t2,
								},
							},
							{
								PreviousState: eval.Pending,
								State: &State{
									Labels:      labels["system + rule + labels2"],
									State:       eval.Normal,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t2,
								},
							},
						},
						t3: {
							{
								PreviousState:       eval.Normal,
								PreviousStateReason: eval.NoData.String(),
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Normal,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t1,
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState:       eval.Normal,
								PreviousStateReason: eval.NoData.String(),
								State: &State{
									Labels:      labels["system + rule + labels2"],
									State:       eval.Normal,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.KeepLast: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Normal,
									StateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t1,
									LastEvaluationTime: t2,
								},
							},
							{
								PreviousState: eval.Pending,
								State: &State{
									Labels:      labels["system + rule + labels2"],
									State:       eval.Alerting,
									StateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
						t3: {
							{
								PreviousState:       eval.Normal,
								PreviousStateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Normal,
									StateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t1,
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState:       eval.Alerting,
								PreviousStateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
								State: &State{
									Labels:      labels["system + rule + labels2"],
									State:       eval.Alerting,
									StateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
				},
			},
			{
				desc:         "t1[1:alerting] t2[NoData] t3[1:alerting] and 'for'=2 at t3",
				ruleMutators: []ngmodels.AlertRuleMutator{ngmodels.WithForNTimes(2)},
				results: map[time.Time]eval.Results{
					t1: {
						newResult(eval.WithState(eval.Alerting), eval.WithLabels(labels1)),
					},
					t2: {
						newResult(eval.WithState(eval.NoData), eval.WithLabels(noDataLabels)),
					},
					t3: {
						newResult(eval.WithState(eval.Alerting), eval.WithLabels(labels1)),
					},
				},
				expectedTransitions: map[ngmodels.NoDataState]map[time.Time][]StateTransition{
					ngmodels.NoData: {
						t3: {
							{
								PreviousState: eval.Pending,
								State: &State{
									Labels: labels["system + rule + labels1"],
									State:  eval.Alerting,
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
										newEvaluation(t3, eval.Alerting),
									},
									StartsAt:           t3,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.Alerting: {
						t3: {
							{
								PreviousState: eval.Pending,
								State: &State{
									Labels: labels["system + rule + labels1"],
									State:  eval.Alerting,
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
										newEvaluation(t3, eval.Alerting),
									},
									StartsAt:           t3,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.OK: {
						t3: {
							{
								PreviousState: eval.Pending,
								State: &State{
									Labels: labels["system + rule + labels1"],
									State:  eval.Alerting,
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
										newEvaluation(t3, eval.Alerting),
									},
									StartsAt:           t3,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.KeepLast: {
						t3: {
							{
								PreviousState: eval.Pending,
								State: &State{
									Labels: labels["system + rule + labels1"],
									State:  eval.Alerting,
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
										newEvaluation(t3, eval.Alerting),
									},
									StartsAt:           t3,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
				},
				expectedTransitionsApplyNoDataErrorToAllStates: map[ngmodels.NoDataState]map[time.Time][]StateTransition{
					ngmodels.Alerting: {
						t3: {
							{
								PreviousState:       eval.Pending,
								PreviousStateReason: eval.NoData.String(),
								State: &State{
									Labels: labels["system + rule + labels1"],
									State:  eval.Alerting,
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
										newEvaluation(t3, eval.Alerting),
									},
									StartsAt:           t3,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.OK: {
						t3: {
							{
								PreviousState:       eval.Normal,
								PreviousStateReason: eval.NoData.String(),
								State: &State{
									Labels: labels["system + rule + labels1"],
									State:  eval.Pending,
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
										newEvaluation(t3, eval.Alerting),
									},
									StartsAt:           t3,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.KeepLast: {
						t3: {
							{
								PreviousState:       eval.Pending,
								PreviousStateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
								State: &State{
									Labels: labels["system + rule + labels1"],
									State:  eval.Alerting,
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
										newEvaluation(t3, eval.Alerting),
									},
									StartsAt:           t3,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
				},
			},
			{
				desc: "t1[NoData] t2[1:normal] t3[1:normal] at t3",
				results: map[time.Time]eval.Results{
					t1: {
						newResult(eval.WithState(eval.NoData), eval.WithLabels(noDataLabels)),
					},
					t2: {
						newResult(eval.WithState(eval.Normal), eval.WithLabels(labels1)),
					},
					t3: {
						newResult(eval.WithState(eval.Normal), eval.WithLabels(labels1)),
					},
				},
				expectedTransitions: map[ngmodels.NoDataState]map[time.Time][]StateTransition{
					ngmodels.NoData: {
						t3: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels: labels["system + rule + labels1"],
									State:  eval.Normal,
									Results: []Evaluation{
										newEvaluation(t2, eval.Normal),
										newEvaluation(t3, eval.Normal),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState: eval.NoData,
								State: &State{
									Labels:      labels["system + rule + no-data"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.Alerting: {
						t3: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels: labels["system + rule + labels1"],
									State:  eval.Normal,
									Results: []Evaluation{
										newEvaluation(t2, eval.Normal),
										newEvaluation(t3, eval.Normal),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState:       eval.Alerting,
								PreviousStateReason: eval.NoData.String(),
								State: &State{
									Labels:      labels["system + rule + no-data"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
									Resolved:           true,
								},
							},
						},
					},
					ngmodels.OK: {
						t3: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels: labels["system + rule + labels1"],
									State:  eval.Normal,
									Results: []Evaluation{
										newEvaluation(t2, eval.Normal),
										newEvaluation(t3, eval.Normal),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState:       eval.Normal,
								PreviousStateReason: eval.NoData.String(),
								State: &State{
									Labels:      labels["system + rule + no-data"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.KeepLast: {
						t3: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels: labels["system + rule + labels1"],
									State:  eval.Normal,
									Results: []Evaluation{
										newEvaluation(t2, eval.Normal),
										newEvaluation(t3, eval.Normal),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState:       eval.Normal,
								PreviousStateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
								State: &State{
									Labels:      labels["system + rule + no-data"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
								},
							},
						},
					},
				},
			},
			{
				desc: "t1[{}:normal] t2[NoData] at t2",
				results: map[time.Time]eval.Results{
					t1: {
						newResult(eval.WithState(eval.Normal)),
					},
					t2: {
						newResult(eval.WithState(eval.NoData), eval.WithLabels(noDataLabels)),
					},
				},
				expectedTransitions: map[ngmodels.NoDataState]map[time.Time][]StateTransition{
					ngmodels.NoData: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels: labels["system + rule + no-data"],
									State:  eval.NoData,
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
					},
					ngmodels.Alerting: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + no-data"],
									State:       eval.Alerting,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
					},
					ngmodels.OK: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + no-data"],
									State:       eval.Normal,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t2,
								},
							},
						},
					},
					ngmodels.KeepLast: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + no-data"],
									State:       eval.Normal,
									StateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t2,
								},
							},
						},
					},
				},
				expectedTransitionsApplyNoDataErrorToAllStates: map[ngmodels.NoDataState]map[time.Time][]StateTransition{
					ngmodels.Alerting: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Alerting,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
					},
					ngmodels.OK: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Normal,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t1,
									LastEvaluationTime: t2,
								},
							},
						},
					},
					ngmodels.KeepLast: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Normal,
									StateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t1,
									LastEvaluationTime: t2,
								},
							},
						},
					},
				},
			},
			{
				desc: "t1[{}:alerting] t2[NoData] t3[NoData] at t2,t3",
				results: map[time.Time]eval.Results{
					t1: {
						newResult(eval.WithState(eval.Alerting)),
					},
					t2: {
						newResult(eval.WithState(eval.NoData), eval.WithLabels(noDataLabels)),
					},
					t3: {
						newResult(eval.WithState(eval.NoData), eval.WithLabels(noDataLabels)),
					},
				},
				expectedTransitions: map[ngmodels.NoDataState]map[time.Time][]StateTransition{
					ngmodels.NoData: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels: labels["system + rule + no-data"],
									State:  eval.NoData,
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
						t3: {
							{
								PreviousState: eval.Alerting,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
									Resolved:           true,
								},
							},
							{
								PreviousState: eval.NoData,
								State: &State{
									Labels: labels["system + rule + no-data"],
									State:  eval.NoData,
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.Alerting: {
						t3: {
							{
								PreviousState: eval.Alerting,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
									Resolved:           true,
								},
							},
							{
								PreviousState:       eval.Alerting,
								PreviousStateReason: eval.NoData.String(),
								State: &State{
									Labels:      labels["system + rule + no-data"],
									State:       eval.Alerting,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.OK: {
						t3: {
							{
								PreviousState: eval.Alerting,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
									Resolved:           true,
								},
							},
							{
								PreviousState:       eval.Normal,
								PreviousStateReason: eval.NoData.String(),
								State: &State{
									Labels:      labels["system + rule + no-data"],
									State:       eval.Normal,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.KeepLast: {
						t3: {
							{
								PreviousState: eval.Alerting,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
									Resolved:           true,
								},
							},
							{
								PreviousState:       eval.Normal,
								PreviousStateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
								State: &State{
									Labels:      labels["system + rule + no-data"],
									State:       eval.Normal,
									StateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t3,
								},
							},
						},
					},
				},
				expectedTransitionsApplyNoDataErrorToAllStates: map[ngmodels.NoDataState]map[time.Time][]StateTransition{
					ngmodels.Alerting: {
						t2: {
							{
								PreviousState: eval.Alerting,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Alerting,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
						t3: {
							{
								PreviousState:       eval.Alerting,
								PreviousStateReason: eval.NoData.String(),
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Alerting,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
										newEvaluation(t2, eval.NoData),
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.OK: {
						t2: {
							{
								PreviousState: eval.Alerting,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Normal,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t2,
									Resolved:           true,
								},
							},
						},
						t3: {
							{
								PreviousState:       eval.Normal,
								PreviousStateReason: eval.NoData.String(),
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Normal,
									StateReason: eval.NoData.String(),
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
										newEvaluation(t2, eval.NoData),
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.KeepLast: {
						t2: {
							{
								PreviousState: eval.Alerting,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Alerting,
									StateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
						t3: {
							{
								PreviousState:       eval.Alerting,
								PreviousStateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Alerting,
									StateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
										newEvaluation(t2, eval.NoData),
										newEvaluation(t3, eval.NoData),
									},
									StartsAt:           t1,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
				},
			},
			{
				desc:         "t1[{}:alerting] t2[NoData] t3[{}:alerting] and 'for'=2 at t2*,t3",
				ruleMutators: []ngmodels.AlertRuleMutator{ngmodels.WithForNTimes(2)},
				results: map[time.Time]eval.Results{
					t1: {
						newResult(eval.WithState(eval.Alerting)),
					},
					t2: {
						newResult(eval.WithState(eval.NoData), eval.WithLabels(noDataLabels)),
					},
					t3: {
						newResult(eval.WithState(eval.Alerting)),
					},
				},
				expectedTransitions: map[ngmodels.NoDataState]map[time.Time][]StateTransition{
					ngmodels.NoData: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels: labels["system + rule + no-data"],
									State:  eval.NoData,
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
						t3: {
							{
								PreviousState: eval.Pending,
								State: &State{
									Labels: labels["system + rule"],
									State:  eval.Alerting,
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
										newEvaluation(t3, eval.Alerting),
									},
									StartsAt:           t3,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.Alerting: {
						t3: {
							{
								PreviousState: eval.Pending,
								State: &State{
									Labels: labels["system + rule"],
									State:  eval.Alerting,
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
										newEvaluation(t3, eval.Alerting),
									},
									StartsAt:           t3,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.OK: {
						t3: {
							{
								PreviousState: eval.Pending,
								State: &State{
									Labels: labels["system + rule"],
									State:  eval.Alerting,
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
										newEvaluation(t3, eval.Alerting),
									},
									StartsAt:           t3,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.KeepLast: {
						t3: {
							{
								PreviousState: eval.Pending,
								State: &State{
									Labels: labels["system + rule"],
									State:  eval.Alerting,
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
										newEvaluation(t3, eval.Alerting),
									},
									StartsAt:           t3,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
				},
				expectedTransitionsApplyNoDataErrorToAllStates: map[ngmodels.NoDataState]map[time.Time][]StateTransition{
					ngmodels.Alerting: {
						t3: {
							{
								PreviousState:       eval.Pending,
								PreviousStateReason: eval.NoData.String(),
								State: &State{
									Labels: labels["system + rule"],
									State:  eval.Alerting,
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
										newEvaluation(t3, eval.Alerting),
									},
									StartsAt:           t3,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.OK: {
						t3: {
							{
								PreviousState:       eval.Normal,
								PreviousStateReason: eval.NoData.String(),
								State: &State{
									Labels: labels["system + rule"],
									State:  eval.Pending,
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
										newEvaluation(t3, eval.Alerting),
									},
									StartsAt:           t3,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.KeepLast: {
						t3: {
							{
								PreviousState:       eval.Pending,
								PreviousStateReason: ngmodels.ConcatReasons(eval.NoData.String(), ngmodels.StateReasonKeepLast),
								State: &State{
									Labels: labels["system + rule"],
									State:  eval.Alerting,
									Results: []Evaluation{
										newEvaluation(t2, eval.NoData),
										newEvaluation(t3, eval.Alerting),
									},
									StartsAt:           t3,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
				},
			},
		}

		for _, tc := range testCases {
			t.Run(tc.desc, func(t *testing.T) {
				executeForEachRule(t, tc)
			})
		}
	})

	t.Run("error", func(t *testing.T) {
		rules := map[ngmodels.ExecutionErrorState]*ngmodels.AlertRule{
			ngmodels.ErrorErrState:    baseRuleWith(ngmodels.WithErrorExecAs(ngmodels.ErrorErrState)),
			ngmodels.AlertingErrState: baseRuleWith(ngmodels.WithErrorExecAs(ngmodels.AlertingErrState)),
			ngmodels.OkErrState:       baseRuleWith(ngmodels.WithErrorExecAs(ngmodels.OkErrState)),
			ngmodels.KeepLastErrState: baseRuleWith(ngmodels.WithErrorExecAs(ngmodels.KeepLastErrState)),
		}

		cacheID := func(lbls data.Labels) string {
			l := ngmodels.InstanceLabels(lbls)
			r, err := l.StringKey()
			if err != nil {
				panic(err)
			}
			return r
		}

		type errorTestCase struct {
			desc                string
			ruleMutators        []ngmodels.AlertRuleMutator
			results             map[time.Time]eval.Results
			expectedTransitions map[ngmodels.ExecutionErrorState]map[time.Time][]StateTransition

			expectedTransitionsApplyNoDataErrorToAllStates map[ngmodels.ExecutionErrorState]map[time.Time][]StateTransition
		}

		executeForEachRule := func(t *testing.T, tc errorTestCase) {
			t.Helper()
			for stateExec, rule := range rules {
				r := rule
				if len(tc.ruleMutators) > 0 {
					r = ngmodels.CopyRule(r)
					for _, mutateRule := range tc.ruleMutators {
						mutateRule(r)
					}
				}
				t.Run(fmt.Sprintf("execute as %s", stateExec), func(t *testing.T) {
					expectedTransitions, ok := tc.expectedTransitionsApplyNoDataErrorToAllStates[stateExec]
					overridden := "[*]"
					if !ok {
						expectedTransitions, ok = tc.expectedTransitions[stateExec]
						overridden = ""
					}
					if !ok {
						require.Fail(t, "no expected state transitions")
					}
					t.Run("applyNoDataErrorToAllStates=true"+overridden, func(t *testing.T) {
						executeTest(t, r, tc.results, expectedTransitions, true)
					})
					t.Run("applyNoDataErrorToAllStates=false", func(t *testing.T) {
						expectedTransitions, ok := tc.expectedTransitions[stateExec]
						if !ok {
							require.Fail(t, "no expected state transitions")
						}
						executeTest(t, r, tc.results, expectedTransitions, false)
					})
				})
			}
		}

		testCases := []errorTestCase{
			{
				desc: "t1[QueryError] at t1",
				results: map[time.Time]eval.Results{
					t1: {
						newResult(eval.WithError(datasourceError)),
					},
				},
				expectedTransitions: map[ngmodels.ExecutionErrorState]map[time.Time][]StateTransition{
					ngmodels.ErrorErrState: {
						t1: {
							{
								PreviousState: eval.Normal,
								State: &State{
									CacheID: cacheID(labels["system + rule"]),
									Labels:  labels["system + rule + datasource-error"],
									State:   eval.Error,
									Error:   datasourceError,
									Results: []Evaluation{
										newEvaluation(t1, eval.Error),
									},
									StartsAt:           t1,
									EndsAt:             t1.Add(ResendDelay * 4),
									LastEvaluationTime: t1,
									Annotations: mergeLabels(baseRule.Annotations, data.Labels{
										"Error": datasourceError.Error(),
									}),
								},
							},
						},
					},
					ngmodels.AlertingErrState: {
						t1: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Alerting,
									StateReason: eval.Error.String(),
									Error:       datasourceError,
									Results: []Evaluation{
										newEvaluation(t1, eval.Error),
									},
									StartsAt:           t1,
									EndsAt:             t1.Add(ResendDelay * 4),
									LastEvaluationTime: t1,
								},
							},
						},
					},
					ngmodels.OkErrState: {
						t1: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Normal,
									StateReason: eval.Error.String(),
									Results: []Evaluation{
										newEvaluation(t1, eval.Error),
									},
									StartsAt:           t1,
									EndsAt:             t1,
									LastEvaluationTime: t1,
								},
							},
						},
					},
					ngmodels.KeepLastErrState: {
						t1: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Normal,
									StateReason: ngmodels.ConcatReasons(eval.Error.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t1, eval.Error),
									},
									StartsAt:           t1,
									EndsAt:             t1,
									LastEvaluationTime: t1,
								},
							},
						},
					},
				},
			},
			{
				desc: "t1[GenericError] at t1",
				results: map[time.Time]eval.Results{
					t1: {
						newResult(eval.WithError(genericError)),
					},
				},
				expectedTransitions: map[ngmodels.ExecutionErrorState]map[time.Time][]StateTransition{
					ngmodels.ErrorErrState: {
						t1: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels: labels["system + rule"],
									State:  eval.Error,
									Error:  genericError,
									Results: []Evaluation{
										newEvaluation(t1, eval.Error),
									},
									StartsAt:           t1,
									EndsAt:             t1.Add(ResendDelay * 4),
									LastEvaluationTime: t1,
									Annotations: mergeLabels(baseRule.Annotations, data.Labels{
										"Error": genericError.Error(),
									}),
								},
							},
						},
					},
					ngmodels.AlertingErrState: {
						t1: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Alerting,
									StateReason: eval.Error.String(),
									Error:       genericError,
									Results: []Evaluation{
										newEvaluation(t1, eval.Error),
									},
									StartsAt:           t1,
									EndsAt:             t1.Add(ResendDelay * 4),
									LastEvaluationTime: t1,
								},
							},
						},
					},
					ngmodels.OkErrState: {
						t1: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Normal,
									StateReason: eval.Error.String(),
									Results: []Evaluation{
										newEvaluation(t1, eval.Error),
									},
									StartsAt:           t1,
									EndsAt:             t1,
									LastEvaluationTime: t1,
								},
							},
						},
					},
					ngmodels.KeepLastErrState: {
						t1: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Normal,
									StateReason: ngmodels.ConcatReasons(eval.Error.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t1, eval.Error),
									},
									StartsAt:           t1,
									EndsAt:             t1,
									LastEvaluationTime: t1,
								},
							},
						},
					},
				},
			},
			{
				desc:         "t1[1:alerting] t2[QueryError] and 'for'=1 at t2",
				ruleMutators: []ngmodels.AlertRuleMutator{ngmodels.WithForNTimes(1)},
				results: map[time.Time]eval.Results{
					t1: {
						newResult(eval.WithState(eval.Alerting), eval.WithLabels(labels1)),
					},
					t2: {
						newResult(eval.WithError(datasourceError)),
					},
				},
				expectedTransitions: map[ngmodels.ExecutionErrorState]map[time.Time][]StateTransition{
					ngmodels.ErrorErrState: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									CacheID: cacheID(labels["system + rule"]),
									Labels:  labels["system + rule + datasource-error"],
									State:   eval.Error,
									Error:   datasourceError,
									Results: []Evaluation{
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
									Annotations: mergeLabels(baseRule.Annotations, data.Labels{
										"Error": datasourceError.Error(),
									}),
								},
							},
						},
					},
					ngmodels.AlertingErrState: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Pending,
									StateReason: eval.Error.String(),
									Error:       datasourceError,
									Results: []Evaluation{
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
					},
					ngmodels.OkErrState: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Normal,
									StateReason: eval.Error.String(),
									Results: []Evaluation{
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t2,
								},
							},
						},
					},
					ngmodels.KeepLastErrState: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Normal,
									StateReason: ngmodels.ConcatReasons(eval.Error.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t2,
								},
							},
						},
					},
				},
				expectedTransitionsApplyNoDataErrorToAllStates: map[ngmodels.ExecutionErrorState]map[time.Time][]StateTransition{
					ngmodels.AlertingErrState: {
						t2: {
							{
								PreviousState: eval.Pending,
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Alerting,
									StateReason: eval.Error.String(),
									Error:       datasourceError,
									Results: []Evaluation{
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
					},
					ngmodels.OkErrState: {
						t2: {
							{
								PreviousState: eval.Pending,
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Normal,
									StateReason: eval.Error.String(),
									Results: []Evaluation{
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t2,
								},
							},
						},
					},
					ngmodels.KeepLastErrState: {
						t2: {
							{
								PreviousState: eval.Pending,
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Alerting,
									StateReason: ngmodels.ConcatReasons(eval.Error.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
					},
				},
			},
			{
				desc: "t1[1:normal] t2[QueryError] at t2",
				results: map[time.Time]eval.Results{
					t1: {
						newResult(eval.WithState(eval.Normal), eval.WithLabels(labels1)),
					},
					t2: {
						newResult(eval.WithError(datasourceError)),
					},
				},
				expectedTransitions: map[ngmodels.ExecutionErrorState]map[time.Time][]StateTransition{
					ngmodels.ErrorErrState: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									CacheID: cacheID(labels["system + rule"]),
									Labels:  labels["system + rule + datasource-error"],
									State:   eval.Error,
									Error:   datasourceError,
									Results: []Evaluation{
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
									Annotations: mergeLabels(baseRule.Annotations, data.Labels{
										"Error": datasourceError.Error(),
									}),
								},
							},
						},
					},
					ngmodels.AlertingErrState: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Alerting,
									StateReason: eval.Error.String(),
									Error:       datasourceError,
									Results: []Evaluation{
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
					},
					ngmodels.OkErrState: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Normal,
									StateReason: eval.Error.String(),
									Results: []Evaluation{
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t2,
								},
							},
						},
					},
					ngmodels.KeepLastErrState: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Normal,
									StateReason: ngmodels.ConcatReasons(eval.Error.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t2,
								},
							},
						},
					},
				},
				expectedTransitionsApplyNoDataErrorToAllStates: map[ngmodels.ExecutionErrorState]map[time.Time][]StateTransition{
					ngmodels.AlertingErrState: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Alerting,
									StateReason: eval.Error.String(),
									Error:       datasourceError,
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
					},
					ngmodels.OkErrState: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Normal,
									StateReason: eval.Error.String(),
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t1,
									EndsAt:             t1,
									LastEvaluationTime: t2,
								},
							},
						},
					},
					ngmodels.KeepLastErrState: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule + labels1"],
									State:       eval.Normal,
									StateReason: ngmodels.ConcatReasons(eval.Error.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t1,
									EndsAt:             t1,
									LastEvaluationTime: t2,
								},
							},
						},
					},
				},
			},
			{
				desc: "t1[QueryError] t2[1:normal] t3[1:normal] at t3",
				results: map[time.Time]eval.Results{
					t1: {
						newResult(eval.WithError(datasourceError)),
					},
					t2: {
						newResult(eval.WithState(eval.Normal), eval.WithLabels(labels1)),
					},
					t3: {
						newResult(eval.WithState(eval.Normal), eval.WithLabels(labels1)),
					},
				},
				expectedTransitions: map[ngmodels.ExecutionErrorState]map[time.Time][]StateTransition{
					ngmodels.ErrorErrState: {
						t3: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels: labels["system + rule + labels1"],
									State:  eval.Normal,
									Results: []Evaluation{
										newEvaluation(t2, eval.Normal),
										newEvaluation(t3, eval.Normal),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState: eval.Error,
								State: &State{
									CacheID:     cacheID(labels["system + rule"]),
									Labels:      labels["system + rule + datasource-error"],
									Error:       datasourceError,
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.Error),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
									Annotations: mergeLabels(baseRule.Annotations, data.Labels{
										"Error": datasourceError.Error(),
									}),
								},
							},
						},
					},
					ngmodels.AlertingErrState: {
						t3: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels: labels["system + rule + labels1"],
									State:  eval.Normal,
									Results: []Evaluation{
										newEvaluation(t2, eval.Normal),
										newEvaluation(t3, eval.Normal),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState:       eval.Alerting,
								PreviousStateReason: eval.Error.String(),
								State: &State{
									Labels:      labels["system + rule"],
									Error:       datasourceError,
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.Error),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
									Resolved:           true,
								},
							},
						},
					},
					ngmodels.OkErrState: {
						t3: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels: labels["system + rule + labels1"],
									State:  eval.Normal,
									Results: []Evaluation{
										newEvaluation(t2, eval.Normal),
										newEvaluation(t3, eval.Normal),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState:       eval.Normal,
								PreviousStateReason: eval.Error.String(),
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.Error),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.KeepLastErrState: {
						t3: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels: labels["system + rule + labels1"],
									State:  eval.Normal,
									Results: []Evaluation{
										newEvaluation(t2, eval.Normal),
										newEvaluation(t3, eval.Normal),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t3,
								},
							},
							{
								PreviousState:       eval.Normal,
								PreviousStateReason: ngmodels.ConcatReasons(eval.Error.String(), ngmodels.StateReasonKeepLast),
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Normal,
									StateReason: ngmodels.StateReasonMissingSeries,
									Results: []Evaluation{
										newEvaluation(t1, eval.Error),
									},
									StartsAt:           t1,
									EndsAt:             t3,
									LastEvaluationTime: t3,
								},
							},
						},
					},
				},
			},
			{
				desc: "t1[{}:normal] t2[QueryError] at t2",
				results: map[time.Time]eval.Results{
					t1: {
						newResult(eval.WithState(eval.Normal)),
					},
					t2: {
						newResult(eval.WithError(datasourceError)),
					},
				},
				expectedTransitions: map[ngmodels.ExecutionErrorState]map[time.Time][]StateTransition{
					ngmodels.ErrorErrState: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									CacheID: cacheID(labels["system + rule"]),
									Labels:  labels["system + rule + datasource-error"],
									State:   eval.Error,
									Error:   datasourceError,
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
									Annotations: mergeLabels(baseRule.Annotations, data.Labels{
										"Error": datasourceError.Error(),
									}),
								},
							},
						},
					},
					ngmodels.AlertingErrState: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Alerting,
									StateReason: eval.Error.String(),
									Error:       datasourceError,
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
					},
					ngmodels.OkErrState: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Normal,
									StateReason: eval.Error.String(),
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t1,
									EndsAt:             t1,
									LastEvaluationTime: t2,
								},
							},
						},
					},
					ngmodels.KeepLastErrState: {
						t2: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Normal,
									StateReason: ngmodels.ConcatReasons(eval.Error.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t1, eval.Normal),
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t1,
									EndsAt:             t1,
									LastEvaluationTime: t2,
								},
							},
						},
					},
				},
			},
			{
				desc:         "t1[{}:alerting] t2[QueryError] and 'for'=1 at t1*,t2",
				ruleMutators: []ngmodels.AlertRuleMutator{ngmodels.WithForNTimes(1)},
				results: map[time.Time]eval.Results{
					t1: {
						newResult(eval.WithState(eval.Alerting)),
					},
					t2: {
						newResult(eval.WithError(datasourceError)),
					},
				},
				expectedTransitions: map[ngmodels.ExecutionErrorState]map[time.Time][]StateTransition{
					ngmodels.ErrorErrState: {
						t1: {
							{
								PreviousState: eval.Normal,
								State: &State{
									Labels: labels["system + rule"],
									State:  eval.Pending,
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
									},
									StartsAt:           t1,
									EndsAt:             t1.Add(ResendDelay * 4),
									LastEvaluationTime: t1,
								},
							},
						},
						t2: {
							{
								PreviousState: eval.Pending,
								State: &State{
									CacheID: cacheID(labels["system + rule"]),
									Labels:  labels["system + rule + datasource-error"],
									State:   eval.Error,
									Error:   datasourceError,
									Results: []Evaluation{
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
									Annotations: mergeLabels(baseRule.Annotations, data.Labels{
										"Error": datasourceError.Error(),
									}),
								},
							},
						},
					},
					ngmodels.AlertingErrState: {
						t2: {
							{
								PreviousState: eval.Pending,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Alerting,
									StateReason: eval.Error.String(),
									Error:       datasourceError,
									Results: []Evaluation{
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
					},
					ngmodels.OkErrState: {
						t2: {
							{
								PreviousState: eval.Pending,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Normal,
									StateReason: eval.Error.String(),
									Results: []Evaluation{
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t2,
								},
							},
						},
					},
					ngmodels.KeepLastErrState: {
						t2: {
							{
								PreviousState: eval.Pending,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Alerting,
									StateReason: ngmodels.ConcatReasons(eval.Error.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
					},
				},
			},
			{
				desc:         "t1[{}:alerting] t2[QueryError] t3[{}:alerting] and 'for'=2 at t2,t3",
				ruleMutators: []ngmodels.AlertRuleMutator{ngmodels.WithForNTimes(2)},
				results: map[time.Time]eval.Results{
					t1: {
						newResult(eval.WithState(eval.Alerting)),
					},
					t2: {
						newResult(eval.WithError(datasourceError)),
					},
					t3: {
						newResult(eval.WithState(eval.Alerting)),
					},
				},
				expectedTransitions: map[ngmodels.ExecutionErrorState]map[time.Time][]StateTransition{
					ngmodels.ErrorErrState: {
						t2: {
							{
								PreviousState: eval.Pending,
								State: &State{
									CacheID: cacheID(labels["system + rule"]),
									Labels:  labels["system + rule + datasource-error"],
									State:   eval.Error,
									Error:   datasourceError,
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t2,
									EndsAt:             t2.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
									Annotations: mergeLabels(baseRule.Annotations, data.Labels{
										"Error": datasourceError.Error(),
									}),
								},
							},
						},
						t3: {
							{
								PreviousState: eval.Error,
								State: &State{
									Labels: labels["system + rule"],
									State:  eval.Pending,
									Results: []Evaluation{
										newEvaluation(t2, eval.Error),
										newEvaluation(t3, eval.Alerting),
									},
									StartsAt:           t3,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.AlertingErrState: {
						t2: {
							{
								PreviousState: eval.Pending,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Pending,
									StateReason: eval.Error.String(),
									Error:       datasourceError,
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t1,
									EndsAt:             t1.Add(ResendDelay * 4), // TODO probably it should be t1 (semantic of Normal)?
									LastEvaluationTime: t2,
								},
							},
						},
						t3: {
							{
								PreviousState:       eval.Pending,
								PreviousStateReason: eval.Error.String(),
								State: &State{
									Labels: labels["system + rule"],
									State:  eval.Alerting,
									Results: []Evaluation{
										newEvaluation(t2, eval.Error),
										newEvaluation(t3, eval.Alerting),
									},
									StartsAt:           t3,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.OkErrState: {
						t2: {
							{
								PreviousState: eval.Pending,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Normal,
									StateReason: eval.Error.String(),
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t2,
								},
							},
						},
						t3: {
							{
								PreviousState:       eval.Normal,
								PreviousStateReason: eval.Error.String(),
								State: &State{
									Labels: labels["system + rule"],
									State:  eval.Pending,
									Results: []Evaluation{
										newEvaluation(t2, eval.Error),
										newEvaluation(t3, eval.Alerting),
									},
									StartsAt:           t3,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
					ngmodels.KeepLastErrState: {
						t2: {
							{
								PreviousState: eval.Pending,
								State: &State{
									Labels:      labels["system + rule"],
									State:       eval.Pending,
									StateReason: ngmodels.ConcatReasons(eval.Error.String(), ngmodels.StateReasonKeepLast),
									Results: []Evaluation{
										newEvaluation(t1, eval.Alerting),
										newEvaluation(t2, eval.Error),
									},
									StartsAt:           t1,
									EndsAt:             t1.Add(ResendDelay * 4),
									LastEvaluationTime: t2,
								},
							},
						},
						t3: {
							{
								PreviousState:       eval.Pending,
								PreviousStateReason: ngmodels.ConcatReasons(eval.Error.String(), ngmodels.StateReasonKeepLast),
								State: &State{
									Labels: labels["system + rule"],
									State:  eval.Alerting,
									Results: []Evaluation{
										newEvaluation(t2, eval.Error),
										newEvaluation(t3, eval.Alerting),
									},
									StartsAt:           t3,
									EndsAt:             t3.Add(ResendDelay * 4),
									LastEvaluationTime: t3,
								},
							},
						},
					},
				},
			},
			{
				desc: "t1[QueryError] t2[{}:normal] at t2",
				results: map[time.Time]eval.Results{
					t1: {
						newResult(eval.WithError(datasourceError)),
					},
					t2: {
						newResult(eval.WithState(eval.Normal)),
					},
				},
				expectedTransitions: map[ngmodels.ExecutionErrorState]map[time.Time][]StateTransition{
					ngmodels.ErrorErrState: {
						t2: {
							{
								PreviousState: eval.Error,
								State: &State{
									Labels: labels["system + rule"],
									State:  eval.Normal,
									Results: []Evaluation{
										newEvaluation(t1, eval.Error),
										newEvaluation(t2, eval.Normal),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t2,
								},
							},
						},
					},
					ngmodels.AlertingErrState: {
						t2: {
							{
								PreviousState:       eval.Alerting,
								PreviousStateReason: eval.Error.String(),
								State: &State{
									Labels: labels["system + rule"],
									State:  eval.Normal,
									Results: []Evaluation{
										newEvaluation(t1, eval.Error),
										newEvaluation(t2, eval.Normal),
									},
									StartsAt:           t2,
									EndsAt:             t2,
									LastEvaluationTime: t2,
									Resolved:           true,
								},
							},
						},
					},
					ngmodels.OkErrState: {
						t2: {
							{
								PreviousState:       eval.Normal,
								PreviousStateReason: eval.Error.String(),
								State: &State{
									Labels: labels["system + rule"],
									State:  eval.Normal,
									Results: []Evaluation{
										newEvaluation(t1, eval.Error),
										newEvaluation(t2, eval.Normal),
									},
									StartsAt:           t1,
									EndsAt:             t1,
									LastEvaluationTime: t2,
								},
							},
						},
					},
					ngmodels.KeepLastErrState: {
						t2: {
							{
								PreviousState:       eval.Normal,
								PreviousStateReason: ngmodels.ConcatReasons(eval.Error.String(), ngmodels.StateReasonKeepLast),
								State: &State{
									Labels: labels["system + rule"],
									State:  eval.Normal,
									Results: []Evaluation{
										newEvaluation(t1, eval.Error),
										newEvaluation(t2, eval.Normal),
									},
									StartsAt:           t1,
									EndsAt:             t1,
									LastEvaluationTime: t2,
								},
							},
						},
					},
				},
			},
		}

		for _, tc := range testCases {
			t.Run(tc.desc, func(t *testing.T) {
				executeForEachRule(t, tc)
			})
		}
	})
}

func setCacheID(s *State) *State {
	if s.CacheID != "" {
		return s
	}
	il := ngmodels.InstanceLabels(s.Labels)
	id, err := il.StringKey()
	if err != nil {
		panic(err)
	}
	s.CacheID = id
	return s
}