wip: limitMaxConcurrency only test cases

packages/runner/src/run.ts

@@ -325,8 +325,7 @@ export async function runSuite(suite: Suite, runner: VitestRunner) {
       else {
         for (let tasksGroup of partitionSuiteChildren(suite)) {
           if (tasksGroup[0].concurrent === true) {
-            const mutex = limit(runner.config.maxConcurrency)
-            await Promise.all(tasksGroup.map(c => mutex(() => runSuiteChild(c, runner))))
+            await Promise.all(tasksGroup.map(c => runSuiteChild(c, runner)))
           }
           else {
             const { sequence } = runner.config
@@ -379,15 +378,19 @@ export async function runSuite(suite: Suite, runner: VitestRunner) {
   }
 }
 
+let limitMaxConcurrency: ReturnType<typeof limit>
+
 async function runSuiteChild(c: Task, runner: VitestRunner) {
   if (c.type === 'test' || c.type === 'custom')
-    return runTest(c, runner)
+    return limitMaxConcurrency(() => runTest(c, runner))
 
   else if (c.type === 'suite')
     return runSuite(c, runner)
 }
 
 export async function runFiles(files: File[], runner: VitestRunner) {
+  limitMaxConcurrency ??= limit(runner.config.maxConcurrency)
+
   for (const file of files) {
     if (!file.tasks.length && !runner.config.passWithNoTests) {
       if (!file.result?.errors?.length) {

test/core/test/concurrent-maxConcurrency.test.ts → test/cli/fixtures/fails/concurrent-suite-deadlock.test.ts

@@ -1,26 +1,25 @@
-import { createDefer } from '@vitest/utils'
 import { describe, test, vi } from 'vitest'
+import { createDefer } from 'vitest/dist/utils.js'
 
-vi.setConfig({ maxConcurrency: 2 })
+// 3 tests depend on each other,
+// so they will deadlock when maxConcurrency < 3
+//
+//  [a]  [b]  [c]
+//   * ->
+//        * ->
+//          <- *
+//     <------
 
-describe('limit for each suite', () => {
-  // this test requires running 3 tests in parallel.
-  // but, currently p-limit is applied for each suite layer,
-  // so tests succeed.
-  //
-  //  [0]  [1]  [2]
-  //   * ->
-  //        * ->
-  //          <- *
-  //     <------
+vi.setConfig({ maxConcurrency: 2 })
 
+describe('wrapper', { concurrent: true, timeout: 500 }, () => {
   const defers = [
     createDefer<void>(),
     createDefer<void>(),
     createDefer<void>(),
   ]
 
-  describe('1st suite', { concurrent: true, concurrentSuite: true }, () => {
+  describe('1st suite', () => {
     test('a', async () => {
       defers[0].resolve()
       await defers[2]
@@ -33,7 +32,7 @@ describe('limit for each suite', () => {
     })
   })
 
-  describe('2nd suite', { concurrent: true, concurrentSuite: true }, () => {
+  describe('2nd suite', () => {
     test('c', async () => {
       await defers[1]
       defers[2].resolve()

test/cli/fixtures/fails/concurrent-test-deadlock.test.ts

@@ -0,0 +1,37 @@
+import { describe, test, vi } from 'vitest'
+import { createDefer } from 'vitest/dist/utils.js'
+
+// 3 tests depend on each other,
+// so they will deadlock when maxConcurrency < 3
+//
+//  [a]  [b]  [c]
+//   * ->
+//        * ->
+//          <- *
+//     <------
+
+vi.setConfig({ maxConcurrency: 2 })
+
+describe('wrapper', { concurrent: true, timeout: 500 }, () => {
+  const defers = [
+    createDefer<void>(),
+    createDefer<void>(),
+    createDefer<void>(),
+  ]
+
+  test('a', async () => {
+    defers[0].resolve()
+    await defers[2]
+  })
+
+  test('b', async () => {
+    await defers[0]
+    defers[1].resolve()
+    await defers[2]
+  })
+
+  test('c', async () => {
+    await defers[1]
+    defers[2].resolve()
+  })
+})

test/cli/test/__snapshots__/fails.test.ts.snap

@@ -2,6 +2,10 @@
 
 exports[`should fail .dot-folder/dot-test.test.ts > .dot-folder/dot-test.test.ts 1`] = `"AssertionError: expected true to be false // Object.is equality"`;
 
+exports[`should fail concurrent-suite-deadlock.test.ts > concurrent-suite-deadlock.test.ts 1`] = `"Error: Test timed out in 500ms."`;
+
+exports[`should fail concurrent-test-deadlock.test.ts > concurrent-test-deadlock.test.ts 1`] = `"Error: Test timed out in 500ms."`;
+
 exports[`should fail each-timeout.test.ts > each-timeout.test.ts 1`] = `"Error: Test timed out in 10ms."`;
 
 exports[`should fail empty.test.ts > empty.test.ts 1`] = `"Error: No test suite found in file <rootDir>/empty.test.ts"`;