Add 'TestAccCognitoIDPManagedLoginBranding_updateFromBasic'.

Author: ewbankkit

internal/service/cognitoidp/managed_login_branding.go

@@ -312,32 +312,41 @@ func (r *managedLoginBrandingResource) Update(ctx context.Context, request resou
 		return
 	}
 
-	// Updated settings work in a PATCH model: https://docs.aws.amazon.com/cognito/latest/developerguide/managed-login-brandingeditor.html#branding-designer-api.
-	var patch string
-	var err error
-	if oldSettings, newSettings := fwflex.StringValueFromFramework(ctx, old.Settings), fwflex.StringValueFromFramework(ctx, new.Settings); oldSettings != "" {
-		patch, err = tfjson.CreateMergePatchFromStrings(oldSettings, newSettings)
+	if oldSettings, newSettings := fwflex.StringValueFromFramework(ctx, old.Settings), fwflex.StringValueFromFramework(ctx, new.Settings); newSettings != oldSettings {
+		if oldSettings == "" {
+			var err error
+			input.Settings, err = tfsmithy.DocumentFromJSONString(newSettings, document.NewLazyDocument)
 
-		if err != nil {
-			response.Diagnostics.AddError("creating JSON merge patch", err.Error())
+			if err != nil {
+				response.Diagnostics.AddError("creating Smithy document", err.Error())
 
-			return
-		}
-		input.UseCognitoProvidedValues = false
-	} else if newSettings != "" {
-		patch = newSettings
-		input.UseCognitoProvidedValues = false
-	}
+				return
+			}
 
-	input.Settings, err = tfsmithy.DocumentFromJSONString(patch, document.NewLazyDocument)
+			input.UseCognitoProvidedValues = false
+		} else if newSettings != "" {
+			// Updated settings work in a PATCH model: https://docs.aws.amazon.com/cognito/latest/developerguide/managed-login-brandingeditor.html#branding-designer-api.
+			patch, err := tfjson.CreateMergePatchFromStrings(oldSettings, newSettings)
 
-	if err != nil {
-		response.Diagnostics.AddError("creating Smithy document", err.Error())
+			if err != nil {
+				response.Diagnostics.AddError("creating JSON merge patch", err.Error())
 
-		return
+				return
+			}
+
+			input.Settings, err = tfsmithy.DocumentFromJSONString(patch, document.NewLazyDocument)
+
+			if err != nil {
+				response.Diagnostics.AddError("creating Smithy document", err.Error())
+
+				return
+			}
+
+			input.UseCognitoProvidedValues = false
+		}
 	}
 
-	_, err = conn.UpdateManagedLoginBranding(ctx, &input)
+	_, err := conn.UpdateManagedLoginBranding(ctx, &input)
 
 	if err != nil {
 		response.Diagnostics.AddError(fmt.Sprintf("updating Cognito Managed Login Branding (%s)", managedLoginBrandingID), err.Error())

internal/service/cognitoidp/managed_login_branding_test.go

@@ -209,6 +209,52 @@ func TestAccCognitoIDPManagedLoginBranding_updateFromBasic(t *testing.T) {
 	})
 }
 
+func TestAccCognitoIDPManagedLoginBranding_updateToBasic(t *testing.T) {
+	ctx := acctest.Context(t)
+	var v awstypes.ManagedLoginBrandingType
+	rName := sdkacctest.RandomWithPrefix(acctest.ResourcePrefix)
+	resourceName := "aws_cognito_managed_login_branding.test"
+
+	resource.ParallelTest(t, resource.TestCase{
+		PreCheck:                 func() { acctest.PreCheck(ctx, t); testAccPreCheckIdentityProvider(ctx, t) },
+		ErrorCheck:               acctest.ErrorCheck(t, names.CognitoIDPServiceID),
+		ProtoV5ProviderFactories: acctest.ProtoV5ProviderFactories,
+		CheckDestroy:             testAccCheckManagedLoginBrandingDestroy(ctx),
+		Steps: []resource.TestStep{
+			{
+				Config: testAccManagedLoginBrandingConfig_settings(rName),
+				Check: resource.ComposeAggregateTestCheckFunc(
+					testAccCheckManagedLoginBrandingExists(ctx, resourceName, &v),
+				),
+				ConfigPlanChecks: resource.ConfigPlanChecks{
+					PreApply: []plancheck.PlanCheck{
+						plancheck.ExpectResourceAction(resourceName, plancheck.ResourceActionCreate),
+					},
+				},
+				ConfigStateChecks: []statecheck.StateCheck{
+					statecheck.ExpectKnownValue(resourceName, tfjsonpath.New("settings"), knownvalue.NotNull()),
+					statecheck.ExpectKnownValue(resourceName, tfjsonpath.New("use_cognito_provided_values"), knownvalue.Bool(false)),
+				},
+			},
+			{
+				Config: testAccManagedLoginBrandingConfig_basic(rName),
+				Check: resource.ComposeAggregateTestCheckFunc(
+					testAccCheckManagedLoginBrandingExists(ctx, resourceName, &v),
+				),
+				ConfigPlanChecks: resource.ConfigPlanChecks{
+					PreApply: []plancheck.PlanCheck{
+						plancheck.ExpectResourceAction(resourceName, plancheck.ResourceActionUpdate),
+					},
+				},
+				ConfigStateChecks: []statecheck.StateCheck{
+					statecheck.ExpectKnownValue(resourceName, tfjsonpath.New("settings"), knownvalue.Null()),
+					statecheck.ExpectKnownValue(resourceName, tfjsonpath.New("use_cognito_provided_values"), knownvalue.Bool(true)),
+				},
+			},
+		},
+	})
+}
+
 func testAccCheckManagedLoginBrandingDestroy(ctx context.Context) resource.TestCheckFunc {
 	return func(s *terraform.State) error {
 		conn := acctest.Provider.Meta().(*conns.AWSClient).CognitoIDPClient(ctx)