expose TestUtils.act() for batching actions in tests

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

@@ -515,4 +515,58 @@ describe('ReactTestUtils', () => {
     ReactTestUtils.renderIntoDocument(<Component />);
     expect(mockArgs.length).toEqual(0);
   });
+
+  it('can use interact to batch effects', () => {
+    function App(props) {
+      React.useEffect(props.callback);
+      return null;
+    }
+    const container = document.createElement('div');
+    document.body.appendChild(container);
+
+    try {
+      let called = false;
+      ReactTestUtils.interact(() => {
+        ReactDOM.render(
+          <App
+            callback={() => {
+              called = true;
+            }}
+          />,
+          container,
+        );
+      });
+
+      expect(called).toBe(true);
+    } finally {
+      document.body.removeChild(container);
+    }
+  });
+
+  it('can use interact to batch effects on updates too', () => {
+    function App() {
+      let [ctr, setCtr] = React.useState(0);
+      return (
+        <button id="button" onClick={() => setCtr(x => x + 1)}>
+          {ctr}
+        </button>
+      );
+    }
+    const container = document.createElement('div');
+    document.body.appendChild(container);
+    let button;
+    try {
+      ReactTestUtils.interact(() => {
+        ReactDOM.render(<App />, container);
+      });
+      button = document.getElementById('button');
+      expect(button.innerHTML).toBe('0');
+      ReactTestUtils.interact(() => {
+        button.dispatchEvent(new MouseEvent('click', {bubbles: true}));
+      });
+      expect(button.innerHTML).toBe('1');
+    } finally {
+      document.body.removeChild(container);
+    }
+  });
 });

packages/react-dom/src/client/ReactDOM.js

@@ -35,6 +35,7 @@ import {
   getPublicRootInstance,
   findHostInstance,
   findHostInstanceWithWarning,
+  flushPassiveEffects,
 } from 'react-reconciler/inline.dom';
 import {createPortal as createPortalImpl} from 'shared/ReactPortal';
 import {canUseDOM} from 'shared/ExecutionEnvironment';
@@ -611,6 +612,13 @@ function createPortal(
   return createPortalImpl(children, container, null, key);
 }
 
+// a helper for tests to scope their actions on the dom
+// batches and flushes effects and updates
+function batchedInteraction(callback: () => void) {
+  batchedUpdates(callback);
+  flushPassiveEffects();
+}
+
 const ReactDOM: Object = {
   createPortal,
 
@@ -822,6 +830,7 @@ const ReactDOM: Object = {
       restoreStateIfNeeded,
       dispatchEvent,
       runEventsInBatch,
+      batchedInteraction,
     ],
   },
 };

packages/react-dom/src/fire/ReactFire.js

@@ -40,6 +40,7 @@ import {
   getPublicRootInstance,
   findHostInstance,
   findHostInstanceWithWarning,
+  flushPassiveEffects,
 } from 'react-reconciler/inline.fire';
 import {createPortal as createPortalImpl} from 'shared/ReactPortal';
 import {canUseDOM} from 'shared/ExecutionEnvironment';
@@ -616,6 +617,13 @@ function createPortal(
   return createPortalImpl(children, container, null, key);
 }
 
+// a helper for tests to scope their actions on the dom
+// batches and flushes effects and updates
+function batchedInteraction(callback: () => void) {
+  batchedUpdates(callback);
+  flushPassiveEffects();
+}
+
 const ReactDOM: Object = {
   createPortal,
 
@@ -827,6 +835,7 @@ const ReactDOM: Object = {
       restoreStateIfNeeded,
       dispatchEvent,
       runEventsInBatch,
+      batchedInteraction,
     ],
   },
 };

packages/react-dom/src/test-utils/ReactTestUtils.js

@@ -38,6 +38,7 @@ const [
   restoreStateIfNeeded,
   dispatchEvent,
   runEventsInBatch,
+  batchedInteraction,
 ] = ReactDOM.__SECRET_INTERNALS_DO_NOT_USE_OR_YOU_WILL_BE_FIRED.Events;
 
 function Event(suffix) {}
@@ -380,6 +381,10 @@ const ReactTestUtils = {
 
   Simulate: null,
   SimulateNative: {},
+
+  interact(callback: () => void) {
+    batchedInteraction(callback);
+  },
 };
 
 /**

packages/react-reconciler/src/ReactFiberReconciler.js

@@ -310,6 +310,7 @@ export {
   flushInteractiveUpdates,
   flushControlled,
   flushSync,
+  flushPassiveEffects,
 };
 
 export function getPublicRootInstance(