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scripts/rollup/shims/facebook-www/ReactTestUtils.js

@@ -11,8 +11,49 @@
 
 'use strict';
 
-const {
-  __SECRET_INTERNALS_DO_NOT_USE_OR_YOU_WILL_BE_FIRED,
-} = require('ReactDOM-fb');
+function getTestUtils() {
+  const ReactDOM = require('ReactDOM-fb');
+  return ReactDOM.__SECRET_INTERNALS_DO_NOT_USE_OR_YOU_WILL_BE_FIRED.ReactTestUtils;
+}
 
-module.exports = __SECRET_INTERNALS_DO_NOT_USE_OR_YOU_WILL_BE_FIRED.ReactTestUtils;
+const TestUtils = {...getTestUtils()};
+
+if (__DEV__) {
+  // Lasciate ogni speranza, voi ch'entrate.
+  //
+  // Some www tests currently rely on require('ReactTestUtils') acting as a lazy
+  // require for the whole ReactDOM implementation. However this is no longer
+  // the case with flat bundles since the implementation doesn't get transformed
+  // by www lazy requires. As a result, if test calls jest.resetModuleRegistry()
+  // in beforeEach(), Enzyme's ReactDOM reference will be stale and won't be
+  // able to share any global state (such as current owner) with the newly reset
+  // React singleton that would be used in classes inside the test cases.
+  // To work around it, I'm making any TestUtils method call proxy to the latest
+  // ReactDOM implementation. There might be a better way to do it but my brain
+  // is fried. If you have ideas, please change it to something more reasonable.
+  //
+  // https://fburl.com/jgn0nh70
+  Object.keys(TestUtils).forEach(key => {
+    Object.defineProperty(TestUtils, key, {
+      get() {
+        return getTestUtils()[key];
+      },
+    });
+  })
+  Object.keys(TestUtils.Simulate).forEach(key => {
+    Object.defineProperty(TestUtils.Simulate, key, {
+      get() {
+        return getTestUtils().Simulate[key];
+      },
+    });
+  });
+  Object.keys(TestUtils.SimulateNative).forEach(key => {
+    Object.defineProperty(TestUtils.SimulateNative, key, {
+      get() {
+        return getTestUtils().SimulateNative[key];
+      },
+    });
+  });
+}
+
+module.exports = TestUtils;