Error when tests finish with pending tasks

packages/react-native-fantom/runtime/setup.js

@@ -70,7 +70,7 @@ const rootContext: Context = {
   beforeAllHooks: [],
   beforeEachHooks: [],
   afterAllHooks: [],
-  afterEachHooks: [],
+  afterEachHooks: [validateEmptyMessageQueue],
   children: [],
   focused: false,
   skipped: false,
@@ -93,8 +93,8 @@ const globalDescribe = (global.describe = (
     beforeAllHooks: [],
     beforeEachHooks: [],
     children: [],
-    focused: focused,
-    skipped: skipped,
+    focused,
+    skipped,
   };
   currentContext.children.push(childContext);
   currentContext = childContext;
@@ -137,8 +137,8 @@ const globalIt =
         title,
         parentContext: currentContext,
         implementation,
-        focused: focused,
-        skipped: skipped,
+        focused,
+        skipped,
       });
     });
 
@@ -388,6 +388,10 @@ function reportTestSuiteResult(testSuiteResult: TestSuiteResult): void {
   );
 }
 
+function validateEmptyMessageQueue(): void {
+  NativeFantom.validateEmptyMessageQueue();
+}
+
 global.$$RunTests$$ = () => {
   reportTestSuiteResult({
     testResults: runSuite(currentContext),

packages/react-native-fantom/src/__tests__/Fantom-itest.js

@@ -17,6 +17,7 @@ import type {Root} from '..';
 import Fantom from '..';
 import * as React from 'react';
 import {ScrollView, Text, TextInput, View} from 'react-native';
+import NativeFantom from 'react-native/src/private/specs/modules/NativeFantom';
 import ensureInstance from 'react-native/src/private/utilities/ensureInstance';
 import ReactNativeElement from 'react-native/src/private/webapis/dom/nodes/ReactNativeElement';
 
@@ -132,6 +133,16 @@ describe('Fantom', () => {
       });
       expect(threw).toBe(true);
     });
+
+    it('should error when any scheduled tasks remain after the test', () => {
+      Fantom.scheduleTask(() => {});
+      expect(() => NativeFantom.validateEmptyMessageQueue()).toThrow(
+        'Exception in HostFunction: MessageQueue is not empty',
+      );
+
+      // Flushing queue to avoid this test failing
+      Fantom.runWorkLoop();
+    });
   });
 
   describe('createRoot', () => {

packages/react-native/Libraries/__tests__/__snapshots__/public-api-test.js.snap

@@ -10482,6 +10482,7 @@ interface Spec extends TurboModule {
   getMountingManagerLogs: (surfaceId: number) => Array<string>;
   flushMessageQueue: () => void;
   flushEventQueue: () => void;
+  validateEmptyMessageQueue: () => void;
   getRenderedOutput: (surfaceId: number, config: RenderFormatOptions) => string;
   reportTestSuiteResultsJSON: (results: string) => void;
 }

packages/react-native/ReactCommon/react/renderer/core/RawProps.cpp

@@ -104,10 +104,6 @@ inline bool isYogaStyleProp(const std::string& prop) {
 }
 } // namespace
 
-RawProps::RawProps() {
-  mode_ = Mode::Empty;
-}
-
 /*
  * Creates an object with given `runtime` and `value`.
  */
@@ -149,18 +145,6 @@ RawProps::RawProps(const RawProps& other) noexcept {
   ignoreYogaStyleProps_ = other.ignoreYogaStyleProps_;
 }
 
-RawProps& RawProps::operator=(const RawProps& other) noexcept {
-  mode_ = other.mode_;
-  if (mode_ == Mode::JSI) {
-    runtime_ = other.runtime_;
-    value_ = jsi::Value(*runtime_, other.value_);
-  } else if (mode_ == Mode::Dynamic) {
-    dynamic_ = other.dynamic_;
-  }
-  ignoreYogaStyleProps_ = other.ignoreYogaStyleProps_;
-  return *this;
-}
-
 void RawProps::parse(const RawPropsParser& parser) noexcept {
   react_native_assert(parser_ == nullptr && "A parser was already assigned.");
   parser_ = &parser;

packages/react-native/ReactCommon/react/renderer/core/RawProps.h

@@ -43,18 +43,18 @@ class RawProps final {
   /*
    * Creates empty RawProps objects.
    */
-  RawProps();
+  RawProps() : mode_(Mode::Empty) {}
 
   /*
    * Creates an object with given `runtime` and `value`.
    */
   RawProps(jsi::Runtime& runtime, const jsi::Value& value) noexcept;
 
   explicit RawProps(const RawProps& rawProps) noexcept;
-  RawProps& operator=(const RawProps& other) noexcept;
-
   RawProps(RawProps&& other) noexcept = default;
-  RawProps& operator=(RawProps&& other) noexcept = default;
+
+  RawProps& operator=(const RawProps& other) noexcept = delete;
+  RawProps& operator=(RawProps&& other) noexcept = delete;
 
   /*
    * Creates an object with given `folly::dynamic` object.
@@ -112,8 +112,9 @@ class RawProps final {
   /*
    * Source artefacts:
    */
+
   // Mode
-  mutable Mode mode_;
+  Mode mode_;
 
   // Case 1: Source data is represented as `jsi::Object`.
   jsi::Runtime* runtime_{};

packages/react-native/src/private/specs/modules/NativeFantom.js

@@ -79,6 +79,7 @@ interface Spec extends TurboModule {
   getMountingManagerLogs: (surfaceId: number) => Array<string>;
   flushMessageQueue: () => void;
   flushEventQueue: () => void;
+  validateEmptyMessageQueue: () => void;
   getRenderedOutput: (surfaceId: number, config: RenderFormatOptions) => string;
   reportTestSuiteResultsJSON: (results: string) => void;
 }

packages/react-native/src/private/webapis/intersectionobserver/__tests__/IntersectionObserver-itest.js

@@ -1507,16 +1507,18 @@ describe('IntersectionObserver', () => {
 
       const node = ensureReactNativeElement(maybeNode);
 
-      observer1 = new IntersectionObserver(() => {});
-      observer2 = new IntersectionObserver(() => {});
+      Fantom.runTask(() => {
+        observer1 = new IntersectionObserver(() => {});
+        observer2 = new IntersectionObserver(() => {});
 
-      observer1.observe(node);
-      observer2.observe(node);
+        observer1.observe(node);
+        observer2.observe(node);
 
-      observer1.unobserve(node);
+        observer1.unobserve(node);
 
-      // The second call shouldn't log errors (that would make the test fail).
-      observer2.unobserve(node);
+        // The second call shouldn't log errors (that would make the test fail).
+        observer2.unobserve(node);
+      });
     });
   });