Use RN global to maintain legacy root behavior

Author: Jack Pope

packages/react-test-renderer/src/ReactTestRenderer.js

@@ -483,15 +483,18 @@ function create(
  }
 
  let createNodeMock = defaultTestOptions.createNodeMock;
- let isConcurrent = true;
+ const isConcurrentOnly =
+ disableLegacyMode === true &&
+ global.IS_REACT_NATIVE_TEST_ENVIRONMENT !== true;
+ let isConcurrent = isConcurrentOnly;
  let isStrictMode = false;
  let concurrentUpdatesByDefault = null;
  if (typeof options === 'object' && options !== null) {
  if (typeof options.createNodeMock === 'function') {
  // $FlowFixMe[incompatible-type] found when upgrading Flow
  createNodeMock = options.createNodeMock;
  }
- if (disableLegacyMode === false) {
+ if (!isConcurrentOnly) {
  isConcurrent = options.unstable_isConcurrent;
  }
  if (options.unstable_strictMode === true) {

packages/react-test-renderer/src/__tests__/ReactTestRenderer-test.internal.js

@@ -17,6 +17,11 @@ const {format: prettyFormat} = require('pretty-format');
 const InternalTestUtils = require('internal-test-utils');
 const waitForAll = InternalTestUtils.waitForAll;
 const act = InternalTestUtils.act;
+const Reconciler = require('react-reconciler/src/ReactFiberReconciler');
+const {
+ ConcurrentRoot,
+ LegacyRoot,
+} = require('react-reconciler/src/ReactRootTags');
 
 // Isolate noop renderer
 jest.resetModules();
@@ -65,6 +70,53 @@ describe('ReactTestRenderer', () => {
  );
  });
 
+ describe('root tags', () => {
+ let createContainerSpy;
+ beforeEach(() => {
+ createContainerSpy = jest.spyOn(Reconciler, 'createContainer');
+ });
+
+ function expectTag(tag) {
+ expect(createContainerSpy).toHaveBeenCalledWith(
+ expect.anything(),
+ tag,
+ null,
+ expect.anything(),
+ null,
+ expect.anything(),
+ expect.anything(),
+ null,
+ );
+ }
+
+ // @gate disableLegacyMode
+ it('should render using concurrent root if disableLegacyMode', () => {
+ ReactTestRenderer.create(<div />);
+ expectTag(ConcurrentRoot);
+ });
+
+ // @gate !disableLegacyMode
+ it('should default to legacy root if not disableLegacyMode', () => {
+ ReactTestRenderer.create(<div />);
+ expectTag(LegacyRoot);
+ });
+
+ it('should allow unstable_isConcurrent if not disableLegacyMode', async () => {
+ ReactTestRenderer.create(<div />, {
+ unstable_isConcurrent: true,
+ });
+ ReactTestRenderer.create(<div />);
+ expectTag(ConcurrentRoot);
+ });
+
+ it('should render legacy root when RN test environment', async () => {
+ global.IS_REACT_NATIVE_TEST_ENVIRONMENT = true;
+ ReactTestRenderer.create(<div />);
+ expectTag(LegacyRoot);
+ global.IS_REACT_NATIVE_TEST_ENVIRONMENT = false;
+ });
+ });
+
  it('renders a simple component', async () => {
  function Link() {
  return <a role="link" />;