Provider Defined Functions direct e2e test (#1476)

Signed-off-by: Christian Mesh <christianmesh1@gmail.com>
Signed-off-by: James Humphries <james@james-humphries.co.uk>
Co-authored-by: James Humphries <james@james-humphries.co.uk>

internal/command/e2etest/provider_functions_test.go

@@ -0,0 +1,75 @@
+package e2etest
+
+import (
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/opentofu/opentofu/internal/e2e"
+)
+
+func TestFunction_Simple(t *testing.T) {
+	// This test reaches out to registry.opentofu.org to download the
+	// test functions provider, so it can only run if network access is allowed
+	skipIfCannotAccessNetwork(t)
+
+	fixturePath := filepath.Join("testdata", "functions")
+	tf := e2e.NewBinary(t, tofuBin, fixturePath)
+
+	// tofu init
+	_, stderr, err := tf.Run("init")
+	if err != nil {
+		t.Errorf("unexpected error: %s", err)
+	}
+	if stderr != "" {
+		t.Errorf("unexpected stderr output:\n%s", stderr)
+	}
+
+	_, stderr, err = tf.Run("plan", "-out=fnplan")
+	if err != nil {
+		t.Errorf("unexpected error: %s", err)
+	}
+	if stderr != "" {
+		t.Errorf("unexpected stderr output:\n%s", stderr)
+	}
+
+	plan, err := tf.Plan("fnplan")
+	if err != nil {
+		t.Errorf("unexpected error: %s", err)
+	}
+
+	if len(plan.Changes.Outputs) != 1 {
+		t.Fatalf("expected 1 outputs, got %d", len(plan.Changes.Outputs))
+	}
+	for _, out := range plan.Changes.Outputs {
+		if !strings.Contains(string(out.After), "Hello Functions") {
+			t.Fatalf("unexpected plan output: %s", string(out.After))
+		}
+	}
+}
+
+func TestFunction_Error(t *testing.T) {
+	// This test reaches out to registry.opentofu.org to download the
+	// test functions provider, so it can only run if network access is allowed
+	skipIfCannotAccessNetwork(t)
+	fixturePath := filepath.Join("testdata", "functions-error")
+	tf := e2e.NewBinary(t, tofuBin, fixturePath)
+
+	// tofu init
+	_, stderr, err := tf.Run("init")
+	if err != nil {
+		t.Errorf("unexpected error: %s", err)
+	}
+	if stderr != "" {
+		t.Errorf("unexpected stderr output:\n%s", stderr)
+	}
+
+	// tofu plan -out=fnplan
+	_, stderr, err = tf.Run("plan", "-out=fnplan")
+	if err == nil {
+		t.Errorf("expected error: %s", err)
+	}
+	if !strings.Contains(stderr, "Call to function \"provider::example::error\" failed") {
+		t.Errorf("unexpected stderr output:\n%s", stderr)
+	}
+}

internal/command/e2etest/testdata/functions-error/main.tf

@@ -0,0 +1,12 @@
+terraform {
+	required_providers {
+		example = {
+			source = "opentofu/testfunctions"
+			version = "1.0.0"
+		}
+	}
+}
+
+output "dummy" {
+	value = provider::example::error()
+}

internal/command/e2etest/testdata/functions/main.tf

@@ -0,0 +1,12 @@
+terraform {
+	required_providers {
+		example = {
+			source = "opentofu/testfunctions"
+			version = "1.0.0"
+		}
+	}
+}
+
+output "dummy" {
+	value = provider::example::echo("Hello Functions")
+}