Codemod tests to it.experimental (#17243)

`it.experimental` marks that a test only works in Experimental builds.

It also asserts that a test does *not* work in the stable builds. The
main benefit is that we're less likely to accidentally expose an
experimental API before we intend. It also forces us to un- mark an
experimental test once it become stable.

packages/react-dom/src/__tests__/ReactDOMHooks-test.js

@@ -105,8 +105,9 @@ describe('ReactDOMHooks', () => {
     expect(labelRef.current.innerHTML).toBe('abc');
   });
 
-  if (__EXPERIMENTAL__) {
-    it('should not bail out when an update is scheduled from within an event handler in Concurrent Mode', () => {
+  it.experimental(
+    'should not bail out when an update is scheduled from within an event handler in Concurrent Mode',
+    () => {
       const {createRef, useCallback, useState} = React;
 
       const Example = ({inputRef, labelRef}) => {
@@ -139,6 +140,6 @@ describe('ReactDOMHooks', () => {
       Scheduler.unstable_flushAll();
 
       expect(labelRef.current.innerHTML).toBe('abc');
-    });
-  }
+    },
+  );
 });

packages/react-dom/src/__tests__/ReactServerRenderingHydration-test.js

@@ -500,8 +500,9 @@ describe('ReactDOMServerHydration', () => {
     expect(element.textContent).toBe('Hello world');
   });
 
-  if (__EXPERIMENTAL__) {
-    it('does not re-enter hydration after committing the first one', () => {
+  it.experimental(
+    'does not re-enter hydration after committing the first one',
+    () => {
       let finalHTML = ReactDOMServer.renderToString(<div />);
       let container = document.createElement('div');
       container.innerHTML = finalHTML;
@@ -514,8 +515,8 @@ describe('ReactDOMServerHydration', () => {
       // warnings.
       root.render(<div />);
       Scheduler.unstable_flushAll();
-    });
-  }
+    },
+  );
 
   it('Suspense + hydration in legacy mode', () => {
     const element = document.createElement('div');

packages/react-dom/src/__tests__/ReactTestUtilsAct-test.js

@@ -125,31 +125,27 @@ describe('ReactTestUtils.act()', () => {
       ]);
     });
 
-    if (__EXPERIMENTAL__) {
-      it('warns in blocking mode', () => {
-        expect(() => {
-          const root = ReactDOM.createBlockingRoot(
-            document.createElement('div'),
-          );
-          root.render(<App />);
-          Scheduler.unstable_flushAll();
-        }).toWarnDev([
-          'An update to App ran an effect, but was not wrapped in act(...)',
-          'An update to App ran an effect, but was not wrapped in act(...)',
-        ]);
-      });
+    it.experimental('warns in blocking mode', () => {
+      expect(() => {
+        const root = ReactDOM.createBlockingRoot(document.createElement('div'));
+        root.render(<App />);
+        Scheduler.unstable_flushAll();
+      }).toWarnDev([
+        'An update to App ran an effect, but was not wrapped in act(...)',
+        'An update to App ran an effect, but was not wrapped in act(...)',
+      ]);
+    });
 
-      it('warns in concurrent mode', () => {
-        expect(() => {
-          const root = ReactDOM.createRoot(document.createElement('div'));
-          root.render(<App />);
-          Scheduler.unstable_flushAll();
-        }).toWarnDev([
-          'An update to App ran an effect, but was not wrapped in act(...)',
-          'An update to App ran an effect, but was not wrapped in act(...)',
-        ]);
-      });
-    }
+    it.experimental('warns in concurrent mode', () => {
+      expect(() => {
+        const root = ReactDOM.createRoot(document.createElement('div'));
+        root.render(<App />);
+        Scheduler.unstable_flushAll();
+      }).toWarnDev([
+        'An update to App ran an effect, but was not wrapped in act(...)',
+        'An update to App ran an effect, but was not wrapped in act(...)',
+      ]);
+    });
   });
 });
 

packages/react-dom/src/__tests__/ReactUnmockedSchedulerWarning-test.js

@@ -27,36 +27,30 @@ it('does not warn when rendering in legacy mode', () => {
   }).toWarnDev([]);
 });
 
-if (__EXPERIMENTAL__) {
-  it('should warn when rendering in concurrent mode', () => {
-    expect(() => {
-      ReactDOM.createRoot(document.createElement('div')).render(<App />);
-    }).toWarnDev(
-      'In Concurrent or Sync modes, the "scheduler" module needs to be mocked ' +
-        'to guarantee consistent behaviour across tests and browsers.',
-      {withoutStack: true},
-    );
-    // does not warn twice
-    expect(() => {
-      ReactDOM.createRoot(document.createElement('div')).render(<App />);
-    }).toWarnDev([]);
-  });
+it.experimental('should warn when rendering in concurrent mode', () => {
+  expect(() => {
+    ReactDOM.createRoot(document.createElement('div')).render(<App />);
+  }).toWarnDev(
+    'In Concurrent or Sync modes, the "scheduler" module needs to be mocked ' +
+      'to guarantee consistent behaviour across tests and browsers.',
+    {withoutStack: true},
+  );
+  // does not warn twice
+  expect(() => {
+    ReactDOM.createRoot(document.createElement('div')).render(<App />);
+  }).toWarnDev([]);
+});
 
-  it('should warn when rendering in blocking mode', () => {
-    expect(() => {
-      ReactDOM.createBlockingRoot(document.createElement('div')).render(
-        <App />,
-      );
-    }).toWarnDev(
-      'In Concurrent or Sync modes, the "scheduler" module needs to be mocked ' +
-        'to guarantee consistent behaviour across tests and browsers.',
-      {withoutStack: true},
-    );
-    // does not warn twice
-    expect(() => {
-      ReactDOM.createBlockingRoot(document.createElement('div')).render(
-        <App />,
-      );
-    }).toWarnDev([]);
-  });
-}
+it.experimental('should warn when rendering in blocking mode', () => {
+  expect(() => {
+    ReactDOM.createBlockingRoot(document.createElement('div')).render(<App />);
+  }).toWarnDev(
+    'In Concurrent or Sync modes, the "scheduler" module needs to be mocked ' +
+      'to guarantee consistent behaviour across tests and browsers.',
+    {withoutStack: true},
+  );
+  // does not warn twice
+  expect(() => {
+    ReactDOM.createBlockingRoot(document.createElement('div')).render(<App />);
+  }).toWarnDev([]);
+});