[tests] Assert scheduler log empty in internalAct (#28737)

We should force `assertLog` to be called before each `act` block to
ensure the queue is empty.

Requires fixing tests:
- #28745
- #28758
- #28759
- #28760
- #28761
- #28762
- #28763
- #28812

packages/internal-test-utils/internalAct.js

@@ -19,6 +19,7 @@ import type {Thenable} from 'shared/ReactTypes';
 import * as Scheduler from 'scheduler/unstable_mock';
 
 import enqueueTask from './enqueueTask';
+import {diff} from 'jest-diff';
 
 export let actingUpdatesScopeDepth: number = 0;
 
@@ -45,6 +46,18 @@ export async function act<T>(scope: () => Thenable<T>): Thenable<T> {
     );
   }
 
+  const actualYields = Scheduler.unstable_clearLog();
+  if (actualYields.length !== 0) {
+    const error = Error(
+      'Log of yielded values is not empty. Call assertLog first.\n\n' +
+        `Received:\n${diff('', actualYields.join('\n'), {
+          omitAnnotationLines: true,
+        })}`,
+    );
+    Error.captureStackTrace(error, act);
+    throw error;
+  }
+
   // $FlowFixMe[cannot-resolve-name]: Flow doesn't know about global Jest object
   if (!jest.isMockFunction(setTimeout)) {
     throw Error(

scripts/flow/environment.js

@@ -332,6 +332,31 @@ declare module 'node:worker_threads' {
   }
 }
 
+declare module 'jest-diff' {
+  declare type CompareKeys = ((a: string, b: string) => number) | void;
+  declare type DiffOptions = {
+    aAnnotation?: string,
+    aColor?: (arg: string) => string,
+    aIndicator?: string,
+    bAnnotation?: string,
+    bColor?: (arg: string) => string,
+    bIndicator?: string,
+    changeColor?: (arg: string) => string,
+    changeLineTrailingSpaceColor?: (arg: string) => string,
+    commonColor?: (arg: string) => string,
+    commonIndicator?: string,
+    commonLineTrailingSpaceColor?: (arg: string) => string,
+    contextLines?: number,
+    emptyFirstOrLastLinePlaceholder?: string,
+    expand?: boolean,
+    includeChangeCounts?: boolean,
+    omitAnnotationLines?: boolean,
+    patchColor?: (arg: string) => string,
+    compareKeys?: CompareKeys,
+  };
+  declare function diff(a: any, b: any, options?: DiffOptions): string;
+}
+
 declare const Bun: {
   hash(
     input: string | $TypedArray | DataView | ArrayBuffer | SharedArrayBuffer,