Reinstating TestStep.mergedConfig() method as terraform and provider …

…blocks are only written when using TestStep.Config. The expectation is that when using TestStep.ConfigDirectoy, the terraform files within the configuration directory will specify the terraform and/or provider blocks as necessary (#150)

helper/resource/testing_new.go

@@ -395,8 +395,15 @@ func runNewTest(ctx context.Context, t testing.T, c TestCase, helper *plugintest
 				}
 			}
 
-			var testCaseProviderConfig string
-			var testStepProviderConfig string
+			hasTerraformBlock, err := cfg.HasTerraformBlock(ctx)
+
+			if err != nil {
+				logging.HelperResourceError(ctx,
+					"Error determining whether configuration contains terraform block",
+					map[string]interface{}{logging.KeyError: err},
+				)
+				t.Fatalf("Error determining whether configuration contains terraform block: %s", err)
+			}
 
 			hasProviderBlock, err := cfg.HasProviderBlock(ctx)
 
@@ -408,18 +415,12 @@ func runNewTest(ctx context.Context, t testing.T, c TestCase, helper *plugintest
 				t.Fatalf("Error determining whether configuration contains provider block: %s", err)
 			}
 
-			if c.hasProviders(ctx) {
-				testCaseProviderConfig = c.providerConfig(ctx, hasProviderBlock)
-			} else {
-				testStepProviderConfig = step.providerConfig(ctx, hasProviderBlock)
-			}
+			mergedConfig := step.mergedConfig(ctx, c, hasTerraformBlock, hasProviderBlock)
 
 			appliedCfg, err = teststep.Configuration(
 				teststep.ConfigurationRequest{
-					Directory:              step.ConfigDirectory,
-					Raw:                    step.Config,
-					TestCaseProviderConfig: testCaseProviderConfig,
-					TestStepProviderConfig: testStepProviderConfig,
+					Directory: step.ConfigDirectory,
+					Raw:       mergedConfig,
 				},
 			)
 

helper/resource/testing_new_config.go

@@ -32,8 +32,15 @@ func testStepNewConfig(ctx context.Context, t testing.T, c TestCase, wd *plugint
 		return fmt.Errorf("Error creating config: %w", err)
 	}
 
-	var testCaseProviderConfig string
-	var testStepProviderConfig string
+	hasTerraformBlock, err := cfg.HasTerraformBlock(ctx)
+
+	if err != nil {
+		logging.HelperResourceError(ctx,
+			"Error determining whether configuration contains terraform block",
+			map[string]interface{}{logging.KeyError: err},
+		)
+		t.Fatalf("Error determining whether configuration contains terraform block: %s", err)
+	}
 
 	hasProviderBlock, err := cfg.HasProviderBlock(ctx)
 
@@ -45,18 +52,12 @@ func testStepNewConfig(ctx context.Context, t testing.T, c TestCase, wd *plugint
 		t.Fatalf("Error determining whether configuration contains provider block: %s", err)
 	}
 
-	if c.hasProviders(ctx) {
-		testCaseProviderConfig = c.providerConfig(ctx, hasProviderBlock)
-	} else {
-		testStepProviderConfig = step.providerConfig(ctx, hasProviderBlock)
-	}
+	mergedConfig := step.mergedConfig(ctx, c, hasTerraformBlock, hasProviderBlock)
 
 	config, err := teststep.Configuration(
 		teststep.ConfigurationRequest{
-			Directory:              step.ConfigDirectory,
-			Raw:                    step.Config,
-			TestCaseProviderConfig: testCaseProviderConfig,
-			TestStepProviderConfig: testStepProviderConfig,
+			Directory: step.ConfigDirectory,
+			Raw:       mergedConfig,
 		},
 	)
 

helper/resource/teststep_providers.go

@@ -9,6 +9,40 @@ import (
 	"strings"
 )
 
+// mergedConfig prepends any necessary terraform configuration blocks to the
+// TestStep Config.
+//
+// If there are ExternalProviders configurations in either the TestCase or
+// TestStep, the terraform configuration block should be included with the
+// step configuration to prevent errors with providers outside the
+// registry.terraform.io hostname or outside the hashicorp namespace.
+// This is only necessary when using TestStep.Config.
+//
+// When TestStep.ConfigDirectory is used, the expectation is that the
+// Terraform configuration files will specify a terraform configuration
+// block and/or provider blocks as necessary.
+func (s TestStep) mergedConfig(ctx context.Context, testCase TestCase, configHasTerraformBlock, configHasProviderBlock bool) string {
+	var config strings.Builder
+
+	// Prevent issues with existing configurations containing the terraform
+	// configuration block.
+	if configHasTerraformBlock {
+		config.WriteString(s.Config)
+
+		return config.String()
+	}
+
+	if testCase.hasProviders(ctx) {
+		config.WriteString(testCase.providerConfig(ctx, configHasProviderBlock))
+	} else {
+		config.WriteString(s.providerConfig(ctx, configHasProviderBlock))
+	}
+
+	config.WriteString(s.Config)
+
+	return config.String()
+}
+
 // providerConfig takes the list of providers in a TestStep and returns a
 // config with only empty provider blocks. This is useful for Import, where no
 // config is provided, but the providers must be defined.