test that Refresh updates Provider fields in state

terraform/context_apply_test.go

@@ -8908,7 +8908,6 @@ func TestContext2Apply_destroyWithLocals(t *testing.T) {
 	p.ApplyFn = testApplyFn
 	p.DiffFn = func(info *InstanceInfo, s *InstanceState, c *ResourceConfig) (*InstanceDiff, error) {
 		d, err := testDiffFn(info, s, c)
-		fmt.Println("DIFF:", d)
 		return d, err
 	}
 

terraform/context_refresh_test.go

@@ -1110,3 +1110,53 @@ func TestContext2Refresh_noDiffHookOnScaleOut(t *testing.T) {
 		t.Fatal("PostDiff should not have been called")
 	}
 }
+
+func TestContext2Refresh_updateProviderInState(t *testing.T) {
+	m := testModule(t, "update-resource-provider")
+	p := testProvider("aws")
+
+	p.DiffFn = testDiffFn
+	p.ApplyFn = testApplyFn
+
+	s := &State{
+		Modules: []*ModuleState{
+			&ModuleState{
+				Path: rootModulePath,
+				Resources: map[string]*ResourceState{
+					"aws_instance.bar": &ResourceState{
+						Type: "aws_instance",
+						Primary: &InstanceState{
+							ID: "foo",
+						},
+						Provider: "provider.aws.baz",
+					},
+				},
+			},
+		},
+	}
+
+	ctx := testContext2(t, &ContextOpts{
+		Module: m,
+		ProviderResolver: ResourceProviderResolverFixed(
+			map[string]ResourceProviderFactory{
+				"aws": testProviderFuncFixed(p),
+			},
+		),
+		State: s,
+	})
+
+	expected := strings.TrimSpace(`
+aws_instance.bar:
+  ID = foo
+  provider = provider.aws.foo`)
+
+	state, err := ctx.Refresh()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	actual := state.String()
+	if actual != expected {
+		t.Fatalf("expected:\n%s\n\ngot:\n%s", expected, actual)
+	}
+}

terraform/test-fixtures/update-resource-provider/main.tf

@@ -0,0 +1,7 @@
+provider "aws" {
+  alias = "foo"
+}
+
+resource "aws_instance" "bar" {
+  provider = "aws.foo"
+}