[ci] Add size-balanced test sequencer for better shard distribution

.github/workflows/runtime_build_and_test.yml

@@ -454,9 +454,11 @@ jobs:
       fail-fast: false
       matrix:
         shard:
-          - 1/3
-          - 2/3
-          - 3/3
+          - 1/5
+          - 2/5
+          - 3/5
+          - 4/5
+          - 5/5
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4

packages/react-devtools-shared/src/__tests__/profilerContext-test.js

@@ -654,7 +654,7 @@ describe('ProfilerContext', () => {
     expect(store.profilerStore.isProfilingBasedOnUserInput).toBe(false);
 
     document.body.removeChild(profilerContainer);
-  });
+  }, 20000);
 
   it('should navigate between commits when the keyboard shortcut is pressed', async () => {
     const Parent = () => <Child />;

scripts/jest/config.base.js

@@ -2,6 +2,7 @@
 
 module.exports = {
   globalSetup: require.resolve('./setupGlobal.js'),
+  testSequencer: require.resolve('./sizeBalancedSequencer.js'),
   modulePathIgnorePatterns: [
     '<rootDir>/scripts/rollup/shims/',
     '<rootDir>/scripts/bench/',

scripts/jest/sizeBalancedSequencer.js

@@ -0,0 +1,28 @@
+'use strict';
+
+const Sequencer = require('@jest/test-sequencer').default;
+const fs = require('fs');
+
+class SizeBalancedSequencer extends Sequencer {
+  shard(tests, {shardIndex, shardCount}) {
+    const shards = Array.from({length: shardCount}, () => ({
+      tests: [],
+      size: 0,
+    }));
+    const sorted = [...tests].sort(
+      (a, b) => fs.statSync(b.path).size - fs.statSync(a.path).size
+    );
+
+    for (let i = 0; i < sorted.length; i++) {
+      const test = sorted[i];
+      const size = fs.statSync(test.path).size;
+      const smallest = shards.reduce((min, s) => (s.size < min.size ? s : min));
+      smallest.tests.push(test);
+      smallest.size += size;
+    }
+
+    return shards[shardIndex - 1].tests;
+  }
+}
+
+module.exports = SizeBalancedSequencer;