Add legacyRoot option, add changeset

Signed-off-by: Axel Hecht <axel@pike.org>

.changeset/three-nails-remember.md

@@ -0,0 +1,7 @@
+---
+'@backstage/test-utils': patch
+---
+
+Add support for React Testing Library 13+, and thus React 18.
+
+We're exposing an additional option to the `render*` methods to enable the [legacyRoot](https://testing-library.com/docs/react-testing-library/api/#legacyroot) flow.

packages/test-utils/api-report.md

@@ -55,6 +55,11 @@ export type ErrorWithContext = {
   context?: ErrorApiErrorContext;
 };
 
+// @public
+export type LegacyRootOption = {
+  legacyRoot?: boolean;
+};
+
 // @public
 export type LogCollector = AsyncLogCollector | SyncLogCollector;
 
@@ -194,13 +199,13 @@ export type MockStorageBucket = {
 // @public
 export function renderInTestApp(
   Component: ComponentType<PropsWithChildren<{}>> | ReactNode,
-  options?: TestAppOptions,
+  options?: TestAppOptions & LegacyRootOption,
 ): Promise<RenderResult>;
 
 // @public
 export function renderWithEffects(
   nodes: ReactElement,
-  options?: Pick<RenderOptions, 'wrapper'>,
+  options?: Pick<RenderOptions, 'wrapper'> & LegacyRootOption,
 ): Promise<RenderResult>;
 
 // @public

packages/test-utils/src/testUtils/appWrappers.tsx

@@ -33,7 +33,7 @@ import {
   createRouteRef,
 } from '@backstage/core-plugin-api';
 import { MatcherFunction, RenderResult } from '@testing-library/react';
-import { renderWithEffects } from './testingLibrary';
+import { renderWithEffects, LegacyRootOption } from './testingLibrary';
 import { defaultApis } from './defaultApis';
 import { mockApis } from './mockApis';
 
@@ -232,7 +232,7 @@ export function wrapInTestApp(
  */
 export async function renderInTestApp(
   Component: ComponentType<PropsWithChildren<{}>> | ReactNode,
-  options: TestAppOptions = {},
+  options: TestAppOptions & LegacyRootOption = {},
 ): Promise<RenderResult> {
   let wrappedElement: React.ReactElement;
   if (Component instanceof Function) {
@@ -240,9 +240,11 @@ export async function renderInTestApp(
   } else {
     wrappedElement = Component as React.ReactElement;
   }
+  const { legacyRoot } = options;
 
   return renderWithEffects(wrappedElement, {
     wrapper: createTestAppWrapper(options),
+    legacyRoot,
   });
 }
 

packages/test-utils/src/testUtils/testingLibrary.ts

@@ -22,6 +22,13 @@ import {
   RenderResult,
 } from '@testing-library/react';
 
+/**
+ * @public
+ * Set legacy mode when using React 18/RTL 13+.
+ * Mock this option while we're working against React 17 or lower.
+ */
+export type LegacyRootOption = { legacyRoot?: boolean };
+
 /**
  * @public
  * Simplifies rendering of async components in by taking care of the wrapping inside act
@@ -36,7 +43,7 @@ import {
  */
 export async function renderWithEffects(
   nodes: ReactElement,
-  options?: Pick<RenderOptions, 'wrapper'>,
+  options?: Pick<RenderOptions, 'wrapper'> & LegacyRootOption,
 ): Promise<RenderResult> {
   let value: RenderResult;
   await act(async () => {