fix: reuse the same environment when isolate and fileParallelism are false (#8889)

Author: sheremet-va

packages/vitest/src/node/config/resolveConfig.ts

@@ -212,9 +212,9 @@ export function resolveConfig(
 }
 
 // run benchmark sequentially by default
-resolved.fileParallelism??=mode!=='benchmark'
+constfileParallelism=options.fileParallelism??mode!=='benchmark'
 
-if(!resolved.fileParallelism){
+if(!fileParallelism){
 // ignore user config, parallelism cannot be implemented without limiting workers
 resolved.maxWorkers=1
 }
@@ -227,7 +227,7 @@ export function resolveConfig(
 }
 
 if(resolved.inspect||resolved.inspectBrk){
-if(resolved.fileParallelism){
+if(resolved.maxWorkers!==1){
 constinspectOption=`--inspect${resolved.inspectBrk ? '-brk' : ''}`
 thrownewError(
 `You cannot use ${inspectOption} without "--no-file-parallelism"`,

packages/vitest/src/node/config/serializeConfig.ts

@@ -11,7 +11,6 @@ export function serializeConfig(project: TestProject): SerializedConfig {
 environmentOptions: config.environmentOptions,
 mode: config.mode,
 isolate: config.isolate,
-fileParallelism: config.fileParallelism,
 maxWorkers: config.maxWorkers,
 base: config.base,
 logHeapUsage: config.logHeapUsage,

packages/vitest/src/node/pool.ts

@@ -391,14 +391,14 @@ function groupSpecs(specs: TestSpecification[], environments: Awaited<ReturnType
 }
 
 constorder=spec.project.config.sequence.groupOrder
+constisolate=spec.project.config.isolate
 
 // Files that have disabled parallelism and default groupOrder are set into their own group
-if(order===0&&spec.project.config.fileParallelism===false){
+if(isolate===true&&order===0&&spec.project.config.maxWorkers===1){
 returnsequential.specs.push([spec])
 }
 
 constmaxWorkers=resolveMaxWorkers(spec.project)
-constisolate=spec.project.config.isolate
 groups[order]||={specs: [], maxWorkers }
 
 // Multiple projects with different maxWorkers but same groupOrder

packages/vitest/src/node/types/config.ts

@@ -984,6 +984,7 @@ export interface ResolvedConfig
 |'bail'
 |'name'
 |'vmMemoryLimit'
+|'fileParallelism'
 >{
 mode: VitestRunMode
 
@@ -1117,7 +1118,6 @@ export type ProjectConfig = Omit<
 mode?: string
 sequencer?: Omit<SequenceOptions,'sequencer'|'seed'>
 deps?: Omit<DepsOptions,'moduleDirectories'>
-fileParallelism?: boolean
 }
 
 exporttypeResolvedProjectConfig=Omit<

packages/vitest/src/runtime/config.ts

@@ -15,7 +15,6 @@ export interface SerializedConfig {
 disableConsoleIntercept: boolean|undefined
 runner: string|undefined
 isolate: boolean
-fileParallelism: boolean
 maxWorkers: number
 mode: 'test'|'benchmark'
 bail: number|undefined

test/config/test/failures.test.ts

@@ -70,31 +70,31 @@ test('shard count can be smaller than count of test files when passWithNoTests',
 })
 
 test('inspect requires changing pool and singleThread/singleFork',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true})
+const{ stderr }=awaitrunVitest({inspect: true,maxWorkers: 4})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect cannot be used with multi-threading',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true,pool: 'threads',fileParallelism: true})
+const{ stderr }=awaitrunVitest({inspect: true,pool: 'threads',fileParallelism: true,maxWorkers: 4})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect in browser mode requires no-file-parallelism',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
+const{ stderr }=awaitrunVitest({inspect: true,maxWorkers: 4,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect-brk cannot be used with multi processing',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true,pool: 'forks',fileParallelism: true})
+const{ stderr }=awaitrunVitest({inspect: true,pool: 'forks',fileParallelism: true,maxWorkers: 4})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect-brk in browser mode requires no-file-parallelism',async()=>{
-const{ stderr }=awaitrunVitest({inspectBrk: true,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
+const{ stderr }=awaitrunVitest({inspectBrk: true,maxWorkers: 4,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
 
 expect(stderr).toMatch('Error: You cannot use --inspect-brk without "--no-file-parallelism"')
 })

test/config/test/pool.test.ts

@@ -41,6 +41,7 @@ test('extended project inherits top-level pool related options', async () => {
 test('project level pool options overwrites top-level',async()=>{
 constconfig=awaitgetConfig({
 pool: 'vmForks',
+maxWorkers: 4,
 fileParallelism: true,
 projects: [{
 extends: true,
@@ -49,7 +50,7 @@ test('project level pool options overwrites top-level', async () => {
 })
 
 expect(config.pool).toBe('vmThreads')
-expect(config.fileParallelism).toBe(false)
+expect(config.maxWorkers).toBe(1)
 })
 
 test('isolated single worker pool receives single testfile at once',async()=>{
@@ -83,6 +84,24 @@ test('non-isolated single worker pool receives all testfiles at once', async ()
  `)
 })
 
+test('non-isolated happy-dom worker pool receives all testfiles at once',async()=>{
+constfiles=awaitgetConfig<string[]>({
+fileParallelism: false,
+isolate: false,
+environment: 'happy-dom',
+sequence: {sequencer: StableTestFileOrderSorter},
+},{include: ['print-testfiles.test.ts','a.test.ts','b.test.ts','c.test.ts']})
+
+expect(files.map(normalizeFilename)).toMatchInlineSnapshot(`
+ [
+ "<process-cwd>/fixtures/pool/a.test.ts",
+ "<process-cwd>/fixtures/pool/b.test.ts",
+ "<process-cwd>/fixtures/pool/c.test.ts",
+ "<process-cwd>/fixtures/pool/print-testfiles.test.ts",
+ ]
+ `)
+})
+
 asyncfunctiongetConfig<T=SerializedConfig>(options: Partial<TestUserConfig>,cliOptions: Partial<TestUserConfig>={}): Promise<T>{
 letconfig: T|undefined
 

test/workspaces/globalTest.ts

@@ -36,9 +36,9 @@ export async function teardown() {
 
 try{
 assert.ok(results.success)
-assert.equal(results.numTotalTestSuites,24)
-assert.equal(results.numTotalTests,29)
-assert.equal(results.numPassedTests,29)
+assert.equal(results.numTotalTestSuites,20)
+assert.equal(results.numTotalTests,25)
+assert.equal(results.numPassedTests,25)
 assert.ok(results.coverageMap)
 
 constshared=results.testResults.filter((r: any)=>r.name.includes('space_shared/test.spec.ts'))

test/workspaces/space-pools/multi-worker.test.ts

@@ -212,9 +212,9 @@ export function resolveConfig(
 }
 
 // run benchmark sequentially by default
-resolved.fileParallelism??=mode!=='benchmark'
+constfileParallelism=options.fileParallelism??mode!=='benchmark'
 
-if(!resolved.fileParallelism){
+if(!fileParallelism){
 // ignore user config, parallelism cannot be implemented without limiting workers
 resolved.maxWorkers=1
 }
@@ -227,7 +227,7 @@ export function resolveConfig(
 }
 
 if(resolved.inspect||resolved.inspectBrk){
-if(resolved.fileParallelism){
+if(resolved.maxWorkers!==1){
 constinspectOption=`--inspect${resolved.inspectBrk ? '-brk' : ''}`
 thrownewError(
 `You cannot use ${inspectOption} without "--no-file-parallelism"`,

test/workspaces/space-pools/single-worker.test.ts

@@ -11,7 +11,6 @@ export function serializeConfig(project: TestProject): SerializedConfig {
 environmentOptions: config.environmentOptions,
 mode: config.mode,
 isolate: config.isolate,
-fileParallelism: config.fileParallelism,
 maxWorkers: config.maxWorkers,
 base: config.base,
 logHeapUsage: config.logHeapUsage,

packages/vitest/src/node/config/resolveConfig.ts

@@ -391,14 +391,14 @@ function groupSpecs(specs: TestSpecification[], environments: Awaited<ReturnType
 }
 
 constorder=spec.project.config.sequence.groupOrder
+constisolate=spec.project.config.isolate
 
 // Files that have disabled parallelism and default groupOrder are set into their own group
-if(order===0&&spec.project.config.fileParallelism===false){
+if(isolate===true&&order===0&&spec.project.config.maxWorkers===1){
 returnsequential.specs.push([spec])
 }
 
 constmaxWorkers=resolveMaxWorkers(spec.project)
-constisolate=spec.project.config.isolate
 groups[order]||={specs: [], maxWorkers }
 
 // Multiple projects with different maxWorkers but same groupOrder

packages/vitest/src/node/config/serializeConfig.ts

@@ -984,6 +984,7 @@ export interface ResolvedConfig
 |'bail'
 |'name'
 |'vmMemoryLimit'
+|'fileParallelism'
 >{
 mode: VitestRunMode
 
@@ -1117,7 +1118,6 @@ export type ProjectConfig = Omit<
 mode?: string
 sequencer?: Omit<SequenceOptions,'sequencer'|'seed'>
 deps?: Omit<DepsOptions,'moduleDirectories'>
-fileParallelism?: boolean
 }
 
 exporttypeResolvedProjectConfig=Omit<

packages/vitest/src/node/pool.ts

@@ -15,7 +15,6 @@ export interface SerializedConfig {
 disableConsoleIntercept: boolean|undefined
 runner: string|undefined
 isolate: boolean
-fileParallelism: boolean
 maxWorkers: number
 mode: 'test'|'benchmark'
 bail: number|undefined

packages/vitest/src/node/types/config.ts

@@ -70,31 +70,31 @@ test('shard count can be smaller than count of test files when passWithNoTests',
 })
 
 test('inspect requires changing pool and singleThread/singleFork',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true})
+const{ stderr }=awaitrunVitest({inspect: true,maxWorkers: 4})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect cannot be used with multi-threading',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true,pool: 'threads',fileParallelism: true})
+const{ stderr }=awaitrunVitest({inspect: true,pool: 'threads',fileParallelism: true,maxWorkers: 4})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect in browser mode requires no-file-parallelism',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
+const{ stderr }=awaitrunVitest({inspect: true,maxWorkers: 4,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect-brk cannot be used with multi processing',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true,pool: 'forks',fileParallelism: true})
+const{ stderr }=awaitrunVitest({inspect: true,pool: 'forks',fileParallelism: true,maxWorkers: 4})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect-brk in browser mode requires no-file-parallelism',async()=>{
-const{ stderr }=awaitrunVitest({inspectBrk: true,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
+const{ stderr }=awaitrunVitest({inspectBrk: true,maxWorkers: 4,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
 
 expect(stderr).toMatch('Error: You cannot use --inspect-brk without "--no-file-parallelism"')
 })

packages/vitest/src/runtime/config.ts

@@ -41,6 +41,7 @@ test('extended project inherits top-level pool related options', async () => {
 test('project level pool options overwrites top-level',async()=>{
 constconfig=awaitgetConfig({
 pool: 'vmForks',
+maxWorkers: 4,
 fileParallelism: true,
 projects: [{
 extends: true,
@@ -49,7 +50,7 @@ test('project level pool options overwrites top-level', async () => {
 })
 
 expect(config.pool).toBe('vmThreads')
-expect(config.fileParallelism).toBe(false)
+expect(config.maxWorkers).toBe(1)
 })
 
 test('isolated single worker pool receives single testfile at once',async()=>{
@@ -83,6 +84,24 @@ test('non-isolated single worker pool receives all testfiles at once', async ()
  `)
 })
 
+test('non-isolated happy-dom worker pool receives all testfiles at once',async()=>{
+constfiles=awaitgetConfig<string[]>({
+fileParallelism: false,
+isolate: false,
+environment: 'happy-dom',
+sequence: {sequencer: StableTestFileOrderSorter},
+},{include: ['print-testfiles.test.ts','a.test.ts','b.test.ts','c.test.ts']})
+
+expect(files.map(normalizeFilename)).toMatchInlineSnapshot(`
+ [
+ "<process-cwd>/fixtures/pool/a.test.ts",
+ "<process-cwd>/fixtures/pool/b.test.ts",
+ "<process-cwd>/fixtures/pool/c.test.ts",
+ "<process-cwd>/fixtures/pool/print-testfiles.test.ts",
+ ]
+ `)
+})
+
 asyncfunctiongetConfig<T=SerializedConfig>(options: Partial<TestUserConfig>,cliOptions: Partial<TestUserConfig>={}): Promise<T>{
 letconfig: T|undefined
 

test/config/test/failures.test.ts

@@ -36,9 +36,9 @@ export async function teardown() {
 
 try{
 assert.ok(results.success)
-assert.equal(results.numTotalTestSuites,24)
-assert.equal(results.numTotalTests,29)
-assert.equal(results.numPassedTests,29)
+assert.equal(results.numTotalTestSuites,20)
+assert.equal(results.numTotalTests,25)
+assert.equal(results.numPassedTests,25)
 assert.ok(results.coverageMap)
 
 constshared=results.testResults.filter((r: any)=>r.name.includes('space_shared/test.spec.ts'))

test/config/test/pool.test.ts

@@ -212,9 +212,9 @@ export function resolveConfig(
 }
 
 // run benchmark sequentially by default
-resolved.fileParallelism??=mode!=='benchmark'
+constfileParallelism=options.fileParallelism??mode!=='benchmark'
 
-if(!resolved.fileParallelism){
+if(!fileParallelism){
 // ignore user config, parallelism cannot be implemented without limiting workers
 resolved.maxWorkers=1
 }
@@ -227,7 +227,7 @@ export function resolveConfig(
 }
 
 if(resolved.inspect||resolved.inspectBrk){
-if(resolved.fileParallelism){
+if(resolved.maxWorkers!==1){
 constinspectOption=`--inspect${resolved.inspectBrk ? '-brk' : ''}`
 thrownewError(
 `You cannot use ${inspectOption} without "--no-file-parallelism"`,

test/workspaces/globalTest.ts

@@ -11,7 +11,6 @@ export function serializeConfig(project: TestProject): SerializedConfig {
 environmentOptions: config.environmentOptions,
 mode: config.mode,
 isolate: config.isolate,
-fileParallelism: config.fileParallelism,
 maxWorkers: config.maxWorkers,
 base: config.base,
 logHeapUsage: config.logHeapUsage,

test/workspaces/space-pools/multi-worker.test.ts

@@ -391,14 +391,14 @@ function groupSpecs(specs: TestSpecification[], environments: Awaited<ReturnType
 }
 
 constorder=spec.project.config.sequence.groupOrder
+constisolate=spec.project.config.isolate
 
 // Files that have disabled parallelism and default groupOrder are set into their own group
-if(order===0&&spec.project.config.fileParallelism===false){
+if(isolate===true&&order===0&&spec.project.config.maxWorkers===1){
 returnsequential.specs.push([spec])
 }
 
 constmaxWorkers=resolveMaxWorkers(spec.project)
-constisolate=spec.project.config.isolate
 groups[order]||={specs: [], maxWorkers }
 
 // Multiple projects with different maxWorkers but same groupOrder

test/workspaces/space-pools/single-worker.test.ts

@@ -984,6 +984,7 @@ export interface ResolvedConfig
 |'bail'
 |'name'
 |'vmMemoryLimit'
+|'fileParallelism'
 >{
 mode: VitestRunMode
 
@@ -1117,7 +1118,6 @@ export type ProjectConfig = Omit<
 mode?: string
 sequencer?: Omit<SequenceOptions,'sequencer'|'seed'>
 deps?: Omit<DepsOptions,'moduleDirectories'>
-fileParallelism?: boolean
 }
 
 exporttypeResolvedProjectConfig=Omit<

packages/vitest/src/node/config/resolveConfig.ts

@@ -15,7 +15,6 @@ export interface SerializedConfig {
 disableConsoleIntercept: boolean|undefined
 runner: string|undefined
 isolate: boolean
-fileParallelism: boolean
 maxWorkers: number
 mode: 'test'|'benchmark'
 bail: number|undefined

packages/vitest/src/node/config/serializeConfig.ts

@@ -70,31 +70,31 @@ test('shard count can be smaller than count of test files when passWithNoTests',
 })
 
 test('inspect requires changing pool and singleThread/singleFork',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true})
+const{ stderr }=awaitrunVitest({inspect: true,maxWorkers: 4})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect cannot be used with multi-threading',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true,pool: 'threads',fileParallelism: true})
+const{ stderr }=awaitrunVitest({inspect: true,pool: 'threads',fileParallelism: true,maxWorkers: 4})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect in browser mode requires no-file-parallelism',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
+const{ stderr }=awaitrunVitest({inspect: true,maxWorkers: 4,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect-brk cannot be used with multi processing',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true,pool: 'forks',fileParallelism: true})
+const{ stderr }=awaitrunVitest({inspect: true,pool: 'forks',fileParallelism: true,maxWorkers: 4})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect-brk in browser mode requires no-file-parallelism',async()=>{
-const{ stderr }=awaitrunVitest({inspectBrk: true,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
+const{ stderr }=awaitrunVitest({inspectBrk: true,maxWorkers: 4,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
 
 expect(stderr).toMatch('Error: You cannot use --inspect-brk without "--no-file-parallelism"')
 })

packages/vitest/src/node/pool.ts

@@ -41,6 +41,7 @@ test('extended project inherits top-level pool related options', async () => {
 test('project level pool options overwrites top-level',async()=>{
 constconfig=awaitgetConfig({
 pool: 'vmForks',
+maxWorkers: 4,
 fileParallelism: true,
 projects: [{
 extends: true,
@@ -49,7 +50,7 @@ test('project level pool options overwrites top-level', async () => {
 })
 
 expect(config.pool).toBe('vmThreads')
-expect(config.fileParallelism).toBe(false)
+expect(config.maxWorkers).toBe(1)
 })
 
 test('isolated single worker pool receives single testfile at once',async()=>{
@@ -83,6 +84,24 @@ test('non-isolated single worker pool receives all testfiles at once', async ()
  `)
 })
 
+test('non-isolated happy-dom worker pool receives all testfiles at once',async()=>{
+constfiles=awaitgetConfig<string[]>({
+fileParallelism: false,
+isolate: false,
+environment: 'happy-dom',
+sequence: {sequencer: StableTestFileOrderSorter},
+},{include: ['print-testfiles.test.ts','a.test.ts','b.test.ts','c.test.ts']})
+
+expect(files.map(normalizeFilename)).toMatchInlineSnapshot(`
+ [
+ "<process-cwd>/fixtures/pool/a.test.ts",
+ "<process-cwd>/fixtures/pool/b.test.ts",
+ "<process-cwd>/fixtures/pool/c.test.ts",
+ "<process-cwd>/fixtures/pool/print-testfiles.test.ts",
+ ]
+ `)
+})
+
 asyncfunctiongetConfig<T=SerializedConfig>(options: Partial<TestUserConfig>,cliOptions: Partial<TestUserConfig>={}): Promise<T>{
 letconfig: T|undefined
 

packages/vitest/src/node/types/config.ts

@@ -36,9 +36,9 @@ export async function teardown() {
 
 try{
 assert.ok(results.success)
-assert.equal(results.numTotalTestSuites,24)
-assert.equal(results.numTotalTests,29)
-assert.equal(results.numPassedTests,29)
+assert.equal(results.numTotalTestSuites,20)
+assert.equal(results.numTotalTests,25)
+assert.equal(results.numPassedTests,25)
 assert.ok(results.coverageMap)
 
 constshared=results.testResults.filter((r: any)=>r.name.includes('space_shared/test.spec.ts'))

packages/vitest/src/runtime/config.ts

@@ -212,9 +212,9 @@ export function resolveConfig(
 }
 
 // run benchmark sequentially by default
-resolved.fileParallelism??=mode!=='benchmark'
+constfileParallelism=options.fileParallelism??mode!=='benchmark'
 
-if(!resolved.fileParallelism){
+if(!fileParallelism){
 // ignore user config, parallelism cannot be implemented without limiting workers
 resolved.maxWorkers=1
 }
@@ -227,7 +227,7 @@ export function resolveConfig(
 }
 
 if(resolved.inspect||resolved.inspectBrk){
-if(resolved.fileParallelism){
+if(resolved.maxWorkers!==1){
 constinspectOption=`--inspect${resolved.inspectBrk ? '-brk' : ''}`
 thrownewError(
 `You cannot use ${inspectOption} without "--no-file-parallelism"`,

test/config/test/failures.test.ts

@@ -11,7 +11,6 @@ export function serializeConfig(project: TestProject): SerializedConfig {
 environmentOptions: config.environmentOptions,
 mode: config.mode,
 isolate: config.isolate,
-fileParallelism: config.fileParallelism,
 maxWorkers: config.maxWorkers,
 base: config.base,
 logHeapUsage: config.logHeapUsage,

test/config/test/pool.test.ts

@@ -391,14 +391,14 @@ function groupSpecs(specs: TestSpecification[], environments: Awaited<ReturnType
 }
 
 constorder=spec.project.config.sequence.groupOrder
+constisolate=spec.project.config.isolate
 
 // Files that have disabled parallelism and default groupOrder are set into their own group
-if(order===0&&spec.project.config.fileParallelism===false){
+if(isolate===true&&order===0&&spec.project.config.maxWorkers===1){
 returnsequential.specs.push([spec])
 }
 
 constmaxWorkers=resolveMaxWorkers(spec.project)
-constisolate=spec.project.config.isolate
 groups[order]||={specs: [], maxWorkers }
 
 // Multiple projects with different maxWorkers but same groupOrder

test/workspaces/globalTest.ts

@@ -984,6 +984,7 @@ export interface ResolvedConfig
 |'bail'
 |'name'
 |'vmMemoryLimit'
+|'fileParallelism'
 >{
 mode: VitestRunMode
 
@@ -1117,7 +1118,6 @@ export type ProjectConfig = Omit<
 mode?: string
 sequencer?: Omit<SequenceOptions,'sequencer'|'seed'>
 deps?: Omit<DepsOptions,'moduleDirectories'>
-fileParallelism?: boolean
 }
 
 exporttypeResolvedProjectConfig=Omit<

test/workspaces/space-pools/multi-worker.test.ts

@@ -15,7 +15,6 @@ export interface SerializedConfig {
 disableConsoleIntercept: boolean|undefined
 runner: string|undefined
 isolate: boolean
-fileParallelism: boolean
 maxWorkers: number
 mode: 'test'|'benchmark'
 bail: number|undefined

test/workspaces/space-pools/single-worker.test.ts

@@ -70,31 +70,31 @@ test('shard count can be smaller than count of test files when passWithNoTests',
 })
 
 test('inspect requires changing pool and singleThread/singleFork',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true})
+const{ stderr }=awaitrunVitest({inspect: true,maxWorkers: 4})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect cannot be used with multi-threading',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true,pool: 'threads',fileParallelism: true})
+const{ stderr }=awaitrunVitest({inspect: true,pool: 'threads',fileParallelism: true,maxWorkers: 4})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect in browser mode requires no-file-parallelism',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
+const{ stderr }=awaitrunVitest({inspect: true,maxWorkers: 4,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect-brk cannot be used with multi processing',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true,pool: 'forks',fileParallelism: true})
+const{ stderr }=awaitrunVitest({inspect: true,pool: 'forks',fileParallelism: true,maxWorkers: 4})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect-brk in browser mode requires no-file-parallelism',async()=>{
-const{ stderr }=awaitrunVitest({inspectBrk: true,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
+const{ stderr }=awaitrunVitest({inspectBrk: true,maxWorkers: 4,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
 
 expect(stderr).toMatch('Error: You cannot use --inspect-brk without "--no-file-parallelism"')
 })

packages/vitest/src/node/config/resolveConfig.ts

@@ -41,6 +41,7 @@ test('extended project inherits top-level pool related options', async () => {
 test('project level pool options overwrites top-level',async()=>{
 constconfig=awaitgetConfig({
 pool: 'vmForks',
+maxWorkers: 4,
 fileParallelism: true,
 projects: [{
 extends: true,
@@ -49,7 +50,7 @@ test('project level pool options overwrites top-level', async () => {
 })
 
 expect(config.pool).toBe('vmThreads')
-expect(config.fileParallelism).toBe(false)
+expect(config.maxWorkers).toBe(1)
 })
 
 test('isolated single worker pool receives single testfile at once',async()=>{
@@ -83,6 +84,24 @@ test('non-isolated single worker pool receives all testfiles at once', async ()
  `)
 })
 
+test('non-isolated happy-dom worker pool receives all testfiles at once',async()=>{
+constfiles=awaitgetConfig<string[]>({
+fileParallelism: false,
+isolate: false,
+environment: 'happy-dom',
+sequence: {sequencer: StableTestFileOrderSorter},
+},{include: ['print-testfiles.test.ts','a.test.ts','b.test.ts','c.test.ts']})
+
+expect(files.map(normalizeFilename)).toMatchInlineSnapshot(`
+ [
+ "<process-cwd>/fixtures/pool/a.test.ts",
+ "<process-cwd>/fixtures/pool/b.test.ts",
+ "<process-cwd>/fixtures/pool/c.test.ts",
+ "<process-cwd>/fixtures/pool/print-testfiles.test.ts",
+ ]
+ `)
+})
+
 asyncfunctiongetConfig<T=SerializedConfig>(options: Partial<TestUserConfig>,cliOptions: Partial<TestUserConfig>={}): Promise<T>{
 letconfig: T|undefined
 

packages/vitest/src/node/config/serializeConfig.ts

@@ -36,9 +36,9 @@ export async function teardown() {
 
 try{
 assert.ok(results.success)
-assert.equal(results.numTotalTestSuites,24)
-assert.equal(results.numTotalTests,29)
-assert.equal(results.numPassedTests,29)
+assert.equal(results.numTotalTestSuites,20)
+assert.equal(results.numTotalTests,25)
+assert.equal(results.numPassedTests,25)
 assert.ok(results.coverageMap)
 
 constshared=results.testResults.filter((r: any)=>r.name.includes('space_shared/test.spec.ts'))

packages/vitest/src/node/pool.ts

@@ -212,9 +212,9 @@ export function resolveConfig(
 }
 
 // run benchmark sequentially by default
-resolved.fileParallelism??=mode!=='benchmark'
+constfileParallelism=options.fileParallelism??mode!=='benchmark'
 
-if(!resolved.fileParallelism){
+if(!fileParallelism){
 // ignore user config, parallelism cannot be implemented without limiting workers
 resolved.maxWorkers=1
 }
@@ -227,7 +227,7 @@ export function resolveConfig(
 }
 
 if(resolved.inspect||resolved.inspectBrk){
-if(resolved.fileParallelism){
+if(resolved.maxWorkers!==1){
 constinspectOption=`--inspect${resolved.inspectBrk ? '-brk' : ''}`
 thrownewError(
 `You cannot use ${inspectOption} without "--no-file-parallelism"`,

packages/vitest/src/node/types/config.ts

@@ -11,7 +11,6 @@ export function serializeConfig(project: TestProject): SerializedConfig {
 environmentOptions: config.environmentOptions,
 mode: config.mode,
 isolate: config.isolate,
-fileParallelism: config.fileParallelism,
 maxWorkers: config.maxWorkers,
 base: config.base,
 logHeapUsage: config.logHeapUsage,

packages/vitest/src/runtime/config.ts

@@ -391,14 +391,14 @@ function groupSpecs(specs: TestSpecification[], environments: Awaited<ReturnType
 }
 
 constorder=spec.project.config.sequence.groupOrder
+constisolate=spec.project.config.isolate
 
 // Files that have disabled parallelism and default groupOrder are set into their own group
-if(order===0&&spec.project.config.fileParallelism===false){
+if(isolate===true&&order===0&&spec.project.config.maxWorkers===1){
 returnsequential.specs.push([spec])
 }
 
 constmaxWorkers=resolveMaxWorkers(spec.project)
-constisolate=spec.project.config.isolate
 groups[order]||={specs: [], maxWorkers }
 
 // Multiple projects with different maxWorkers but same groupOrder

test/config/test/failures.test.ts

@@ -984,6 +984,7 @@ export interface ResolvedConfig
 |'bail'
 |'name'
 |'vmMemoryLimit'
+|'fileParallelism'
 >{
 mode: VitestRunMode
 
@@ -1117,7 +1118,6 @@ export type ProjectConfig = Omit<
 mode?: string
 sequencer?: Omit<SequenceOptions,'sequencer'|'seed'>
 deps?: Omit<DepsOptions,'moduleDirectories'>
-fileParallelism?: boolean
 }
 
 exporttypeResolvedProjectConfig=Omit<

test/config/test/pool.test.ts

@@ -15,7 +15,6 @@ export interface SerializedConfig {
 disableConsoleIntercept: boolean|undefined
 runner: string|undefined
 isolate: boolean
-fileParallelism: boolean
 maxWorkers: number
 mode: 'test'|'benchmark'
 bail: number|undefined

test/workspaces/globalTest.ts

@@ -70,31 +70,31 @@ test('shard count can be smaller than count of test files when passWithNoTests',
 })
 
 test('inspect requires changing pool and singleThread/singleFork',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true})
+const{ stderr }=awaitrunVitest({inspect: true,maxWorkers: 4})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect cannot be used with multi-threading',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true,pool: 'threads',fileParallelism: true})
+const{ stderr }=awaitrunVitest({inspect: true,pool: 'threads',fileParallelism: true,maxWorkers: 4})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect in browser mode requires no-file-parallelism',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
+const{ stderr }=awaitrunVitest({inspect: true,maxWorkers: 4,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect-brk cannot be used with multi processing',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true,pool: 'forks',fileParallelism: true})
+const{ stderr }=awaitrunVitest({inspect: true,pool: 'forks',fileParallelism: true,maxWorkers: 4})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect-brk in browser mode requires no-file-parallelism',async()=>{
-const{ stderr }=awaitrunVitest({inspectBrk: true,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
+const{ stderr }=awaitrunVitest({inspectBrk: true,maxWorkers: 4,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
 
 expect(stderr).toMatch('Error: You cannot use --inspect-brk without "--no-file-parallelism"')
 })

test/workspaces/space-pools/multi-worker.test.ts

@@ -41,6 +41,7 @@ test('extended project inherits top-level pool related options', async () => {
 test('project level pool options overwrites top-level',async()=>{
 constconfig=awaitgetConfig({
 pool: 'vmForks',
+maxWorkers: 4,
 fileParallelism: true,
 projects: [{
 extends: true,
@@ -49,7 +50,7 @@ test('project level pool options overwrites top-level', async () => {
 })
 
 expect(config.pool).toBe('vmThreads')
-expect(config.fileParallelism).toBe(false)
+expect(config.maxWorkers).toBe(1)
 })
 
 test('isolated single worker pool receives single testfile at once',async()=>{
@@ -83,6 +84,24 @@ test('non-isolated single worker pool receives all testfiles at once', async ()
  `)
 })
 
+test('non-isolated happy-dom worker pool receives all testfiles at once',async()=>{
+constfiles=awaitgetConfig<string[]>({
+fileParallelism: false,
+isolate: false,
+environment: 'happy-dom',
+sequence: {sequencer: StableTestFileOrderSorter},
+},{include: ['print-testfiles.test.ts','a.test.ts','b.test.ts','c.test.ts']})
+
+expect(files.map(normalizeFilename)).toMatchInlineSnapshot(`
+ [
+ "<process-cwd>/fixtures/pool/a.test.ts",
+ "<process-cwd>/fixtures/pool/b.test.ts",
+ "<process-cwd>/fixtures/pool/c.test.ts",
+ "<process-cwd>/fixtures/pool/print-testfiles.test.ts",
+ ]
+ `)
+})
+
 asyncfunctiongetConfig<T=SerializedConfig>(options: Partial<TestUserConfig>,cliOptions: Partial<TestUserConfig>={}): Promise<T>{
 letconfig: T|undefined
 

test/workspaces/space-pools/single-worker.test.ts

@@ -36,9 +36,9 @@ export async function teardown() {
 
 try{
 assert.ok(results.success)
-assert.equal(results.numTotalTestSuites,24)
-assert.equal(results.numTotalTests,29)
-assert.equal(results.numPassedTests,29)
+assert.equal(results.numTotalTestSuites,20)
+assert.equal(results.numTotalTests,25)
+assert.equal(results.numPassedTests,25)
 assert.ok(results.coverageMap)
 
 constshared=results.testResults.filter((r: any)=>r.name.includes('space_shared/test.spec.ts'))

packages/vitest/src/node/config/resolveConfig.ts

@@ -212,9 +212,9 @@ export function resolveConfig(
 }
 
 // run benchmark sequentially by default
-resolved.fileParallelism??=mode!=='benchmark'
+constfileParallelism=options.fileParallelism??mode!=='benchmark'
 
-if(!resolved.fileParallelism){
+if(!fileParallelism){
 // ignore user config, parallelism cannot be implemented without limiting workers
 resolved.maxWorkers=1
 }
@@ -227,7 +227,7 @@ export function resolveConfig(
 }
 
 if(resolved.inspect||resolved.inspectBrk){
-if(resolved.fileParallelism){
+if(resolved.maxWorkers!==1){
 constinspectOption=`--inspect${resolved.inspectBrk ? '-brk' : ''}`
 thrownewError(
 `You cannot use ${inspectOption} without "--no-file-parallelism"`,

packages/vitest/src/node/config/serializeConfig.ts

@@ -11,7 +11,6 @@ export function serializeConfig(project: TestProject): SerializedConfig {
 environmentOptions: config.environmentOptions,
 mode: config.mode,
 isolate: config.isolate,
-fileParallelism: config.fileParallelism,
 maxWorkers: config.maxWorkers,
 base: config.base,
 logHeapUsage: config.logHeapUsage,

packages/vitest/src/node/pool.ts

@@ -391,14 +391,14 @@ function groupSpecs(specs: TestSpecification[], environments: Awaited<ReturnType
 }
 
 constorder=spec.project.config.sequence.groupOrder
+constisolate=spec.project.config.isolate
 
 // Files that have disabled parallelism and default groupOrder are set into their own group
-if(order===0&&spec.project.config.fileParallelism===false){
+if(isolate===true&&order===0&&spec.project.config.maxWorkers===1){
 returnsequential.specs.push([spec])
 }
 
 constmaxWorkers=resolveMaxWorkers(spec.project)
-constisolate=spec.project.config.isolate
 groups[order]||={specs: [], maxWorkers }
 
 // Multiple projects with different maxWorkers but same groupOrder

packages/vitest/src/node/types/config.ts

@@ -984,6 +984,7 @@ export interface ResolvedConfig
 |'bail'
 |'name'
 |'vmMemoryLimit'
+|'fileParallelism'
 >{
 mode: VitestRunMode
 
@@ -1117,7 +1118,6 @@ export type ProjectConfig = Omit<
 mode?: string
 sequencer?: Omit<SequenceOptions,'sequencer'|'seed'>
 deps?: Omit<DepsOptions,'moduleDirectories'>
-fileParallelism?: boolean
 }
 
 exporttypeResolvedProjectConfig=Omit<

packages/vitest/src/runtime/config.ts

@@ -15,7 +15,6 @@ export interface SerializedConfig {
 disableConsoleIntercept: boolean|undefined
 runner: string|undefined
 isolate: boolean
-fileParallelism: boolean
 maxWorkers: number
 mode: 'test'|'benchmark'
 bail: number|undefined

test/config/test/failures.test.ts

@@ -70,31 +70,31 @@ test('shard count can be smaller than count of test files when passWithNoTests',
 })
 
 test('inspect requires changing pool and singleThread/singleFork',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true})
+const{ stderr }=awaitrunVitest({inspect: true,maxWorkers: 4})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect cannot be used with multi-threading',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true,pool: 'threads',fileParallelism: true})
+const{ stderr }=awaitrunVitest({inspect: true,pool: 'threads',fileParallelism: true,maxWorkers: 4})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect in browser mode requires no-file-parallelism',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
+const{ stderr }=awaitrunVitest({inspect: true,maxWorkers: 4,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect-brk cannot be used with multi processing',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true,pool: 'forks',fileParallelism: true})
+const{ stderr }=awaitrunVitest({inspect: true,pool: 'forks',fileParallelism: true,maxWorkers: 4})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect-brk in browser mode requires no-file-parallelism',async()=>{
-const{ stderr }=awaitrunVitest({inspectBrk: true,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
+const{ stderr }=awaitrunVitest({inspectBrk: true,maxWorkers: 4,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
 
 expect(stderr).toMatch('Error: You cannot use --inspect-brk without "--no-file-parallelism"')
 })

test/config/test/pool.test.ts

@@ -41,6 +41,7 @@ test('extended project inherits top-level pool related options', async () => {
 test('project level pool options overwrites top-level',async()=>{
 constconfig=awaitgetConfig({
 pool: 'vmForks',
+maxWorkers: 4,
 fileParallelism: true,
 projects: [{
 extends: true,
@@ -49,7 +50,7 @@ test('project level pool options overwrites top-level', async () => {
 })
 
 expect(config.pool).toBe('vmThreads')
-expect(config.fileParallelism).toBe(false)
+expect(config.maxWorkers).toBe(1)
 })
 
 test('isolated single worker pool receives single testfile at once',async()=>{
@@ -83,6 +84,24 @@ test('non-isolated single worker pool receives all testfiles at once', async ()
  `)
 })
 
+test('non-isolated happy-dom worker pool receives all testfiles at once',async()=>{
+constfiles=awaitgetConfig<string[]>({
+fileParallelism: false,
+isolate: false,
+environment: 'happy-dom',
+sequence: {sequencer: StableTestFileOrderSorter},
+},{include: ['print-testfiles.test.ts','a.test.ts','b.test.ts','c.test.ts']})
+
+expect(files.map(normalizeFilename)).toMatchInlineSnapshot(`
+ [
+ "<process-cwd>/fixtures/pool/a.test.ts",
+ "<process-cwd>/fixtures/pool/b.test.ts",
+ "<process-cwd>/fixtures/pool/c.test.ts",
+ "<process-cwd>/fixtures/pool/print-testfiles.test.ts",
+ ]
+ `)
+})
+
 asyncfunctiongetConfig<T=SerializedConfig>(options: Partial<TestUserConfig>,cliOptions: Partial<TestUserConfig>={}): Promise<T>{
 letconfig: T|undefined
 

test/workspaces/globalTest.ts

@@ -36,9 +36,9 @@ export async function teardown() {
 
 try{
 assert.ok(results.success)
-assert.equal(results.numTotalTestSuites,24)
-assert.equal(results.numTotalTests,29)
-assert.equal(results.numPassedTests,29)
+assert.equal(results.numTotalTestSuites,20)
+assert.equal(results.numTotalTests,25)
+assert.equal(results.numPassedTests,25)
 assert.ok(results.coverageMap)
 
 constshared=results.testResults.filter((r: any)=>r.name.includes('space_shared/test.spec.ts'))

test/workspaces/space-pools/multi-worker.test.ts

@@ -212,9 +212,9 @@ export function resolveConfig(
 }
 
 // run benchmark sequentially by default
-resolved.fileParallelism??=mode!=='benchmark'
+constfileParallelism=options.fileParallelism??mode!=='benchmark'
 
-if(!resolved.fileParallelism){
+if(!fileParallelism){
 // ignore user config, parallelism cannot be implemented without limiting workers
 resolved.maxWorkers=1
 }
@@ -227,7 +227,7 @@ export function resolveConfig(
 }
 
 if(resolved.inspect||resolved.inspectBrk){
-if(resolved.fileParallelism){
+if(resolved.maxWorkers!==1){
 constinspectOption=`--inspect${resolved.inspectBrk ? '-brk' : ''}`
 thrownewError(
 `You cannot use ${inspectOption} without "--no-file-parallelism"`,

test/workspaces/space-pools/single-worker.test.ts

@@ -11,7 +11,6 @@ export function serializeConfig(project: TestProject): SerializedConfig {
 environmentOptions: config.environmentOptions,
 mode: config.mode,
 isolate: config.isolate,
-fileParallelism: config.fileParallelism,
 maxWorkers: config.maxWorkers,
 base: config.base,
 logHeapUsage: config.logHeapUsage,

packages/vitest/src/node/config/resolveConfig.ts

@@ -391,14 +391,14 @@ function groupSpecs(specs: TestSpecification[], environments: Awaited<ReturnType
 }
 
 constorder=spec.project.config.sequence.groupOrder
+constisolate=spec.project.config.isolate
 
 // Files that have disabled parallelism and default groupOrder are set into their own group
-if(order===0&&spec.project.config.fileParallelism===false){
+if(isolate===true&&order===0&&spec.project.config.maxWorkers===1){
 returnsequential.specs.push([spec])
 }
 
 constmaxWorkers=resolveMaxWorkers(spec.project)
-constisolate=spec.project.config.isolate
 groups[order]||={specs: [], maxWorkers }
 
 // Multiple projects with different maxWorkers but same groupOrder

packages/vitest/src/node/config/serializeConfig.ts

@@ -984,6 +984,7 @@ export interface ResolvedConfig
 |'bail'
 |'name'
 |'vmMemoryLimit'
+|'fileParallelism'
 >{
 mode: VitestRunMode
 
@@ -1117,7 +1118,6 @@ export type ProjectConfig = Omit<
 mode?: string
 sequencer?: Omit<SequenceOptions,'sequencer'|'seed'>
 deps?: Omit<DepsOptions,'moduleDirectories'>
-fileParallelism?: boolean
 }
 
 exporttypeResolvedProjectConfig=Omit<

packages/vitest/src/node/pool.ts

@@ -15,7 +15,6 @@ export interface SerializedConfig {
 disableConsoleIntercept: boolean|undefined
 runner: string|undefined
 isolate: boolean
-fileParallelism: boolean
 maxWorkers: number
 mode: 'test'|'benchmark'
 bail: number|undefined

packages/vitest/src/node/types/config.ts

@@ -70,31 +70,31 @@ test('shard count can be smaller than count of test files when passWithNoTests',
 })
 
 test('inspect requires changing pool and singleThread/singleFork',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true})
+const{ stderr }=awaitrunVitest({inspect: true,maxWorkers: 4})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect cannot be used with multi-threading',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true,pool: 'threads',fileParallelism: true})
+const{ stderr }=awaitrunVitest({inspect: true,pool: 'threads',fileParallelism: true,maxWorkers: 4})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect in browser mode requires no-file-parallelism',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
+const{ stderr }=awaitrunVitest({inspect: true,maxWorkers: 4,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect-brk cannot be used with multi processing',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true,pool: 'forks',fileParallelism: true})
+const{ stderr }=awaitrunVitest({inspect: true,pool: 'forks',fileParallelism: true,maxWorkers: 4})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect-brk in browser mode requires no-file-parallelism',async()=>{
-const{ stderr }=awaitrunVitest({inspectBrk: true,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
+const{ stderr }=awaitrunVitest({inspectBrk: true,maxWorkers: 4,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
 
 expect(stderr).toMatch('Error: You cannot use --inspect-brk without "--no-file-parallelism"')
 })

packages/vitest/src/runtime/config.ts

@@ -41,6 +41,7 @@ test('extended project inherits top-level pool related options', async () => {
 test('project level pool options overwrites top-level',async()=>{
 constconfig=awaitgetConfig({
 pool: 'vmForks',
+maxWorkers: 4,
 fileParallelism: true,
 projects: [{
 extends: true,
@@ -49,7 +50,7 @@ test('project level pool options overwrites top-level', async () => {
 })
 
 expect(config.pool).toBe('vmThreads')
-expect(config.fileParallelism).toBe(false)
+expect(config.maxWorkers).toBe(1)
 })
 
 test('isolated single worker pool receives single testfile at once',async()=>{
@@ -83,6 +84,24 @@ test('non-isolated single worker pool receives all testfiles at once', async ()
  `)
 })
 
+test('non-isolated happy-dom worker pool receives all testfiles at once',async()=>{
+constfiles=awaitgetConfig<string[]>({
+fileParallelism: false,
+isolate: false,
+environment: 'happy-dom',
+sequence: {sequencer: StableTestFileOrderSorter},
+},{include: ['print-testfiles.test.ts','a.test.ts','b.test.ts','c.test.ts']})
+
+expect(files.map(normalizeFilename)).toMatchInlineSnapshot(`
+ [
+ "<process-cwd>/fixtures/pool/a.test.ts",
+ "<process-cwd>/fixtures/pool/b.test.ts",
+ "<process-cwd>/fixtures/pool/c.test.ts",
+ "<process-cwd>/fixtures/pool/print-testfiles.test.ts",
+ ]
+ `)
+})
+
 asyncfunctiongetConfig<T=SerializedConfig>(options: Partial<TestUserConfig>,cliOptions: Partial<TestUserConfig>={}): Promise<T>{
 letconfig: T|undefined
 

test/config/test/failures.test.ts

@@ -36,9 +36,9 @@ export async function teardown() {
 
 try{
 assert.ok(results.success)
-assert.equal(results.numTotalTestSuites,24)
-assert.equal(results.numTotalTests,29)
-assert.equal(results.numPassedTests,29)
+assert.equal(results.numTotalTestSuites,20)
+assert.equal(results.numTotalTests,25)
+assert.equal(results.numPassedTests,25)
 assert.ok(results.coverageMap)
 
 constshared=results.testResults.filter((r: any)=>r.name.includes('space_shared/test.spec.ts'))

test/config/test/pool.test.ts

@@ -212,9 +212,9 @@ export function resolveConfig(
 }
 
 // run benchmark sequentially by default
-resolved.fileParallelism??=mode!=='benchmark'
+constfileParallelism=options.fileParallelism??mode!=='benchmark'
 
-if(!resolved.fileParallelism){
+if(!fileParallelism){
 // ignore user config, parallelism cannot be implemented without limiting workers
 resolved.maxWorkers=1
 }
@@ -227,7 +227,7 @@ export function resolveConfig(
 }
 
 if(resolved.inspect||resolved.inspectBrk){
-if(resolved.fileParallelism){
+if(resolved.maxWorkers!==1){
 constinspectOption=`--inspect${resolved.inspectBrk ? '-brk' : ''}`
 thrownewError(
 `You cannot use ${inspectOption} without "--no-file-parallelism"`,

test/workspaces/globalTest.ts

@@ -11,7 +11,6 @@ export function serializeConfig(project: TestProject): SerializedConfig {
 environmentOptions: config.environmentOptions,
 mode: config.mode,
 isolate: config.isolate,
-fileParallelism: config.fileParallelism,
 maxWorkers: config.maxWorkers,
 base: config.base,
 logHeapUsage: config.logHeapUsage,

test/workspaces/space-pools/multi-worker.test.ts

@@ -391,14 +391,14 @@ function groupSpecs(specs: TestSpecification[], environments: Awaited<ReturnType
 }
 
 constorder=spec.project.config.sequence.groupOrder
+constisolate=spec.project.config.isolate
 
 // Files that have disabled parallelism and default groupOrder are set into their own group
-if(order===0&&spec.project.config.fileParallelism===false){
+if(isolate===true&&order===0&&spec.project.config.maxWorkers===1){
 returnsequential.specs.push([spec])
 }
 
 constmaxWorkers=resolveMaxWorkers(spec.project)
-constisolate=spec.project.config.isolate
 groups[order]||={specs: [], maxWorkers }
 
 // Multiple projects with different maxWorkers but same groupOrder

test/workspaces/space-pools/single-worker.test.ts

@@ -984,6 +984,7 @@ export interface ResolvedConfig
 |'bail'
 |'name'
 |'vmMemoryLimit'
+|'fileParallelism'
 >{
 mode: VitestRunMode
 
@@ -1117,7 +1118,6 @@ export type ProjectConfig = Omit<
 mode?: string
 sequencer?: Omit<SequenceOptions,'sequencer'|'seed'>
 deps?: Omit<DepsOptions,'moduleDirectories'>
-fileParallelism?: boolean
 }
 
 exporttypeResolvedProjectConfig=Omit<

packages/vitest/src/node/config/resolveConfig.ts

@@ -15,7 +15,6 @@ export interface SerializedConfig {
 disableConsoleIntercept: boolean|undefined
 runner: string|undefined
 isolate: boolean
-fileParallelism: boolean
 maxWorkers: number
 mode: 'test'|'benchmark'
 bail: number|undefined

packages/vitest/src/node/config/serializeConfig.ts

@@ -70,31 +70,31 @@ test('shard count can be smaller than count of test files when passWithNoTests',
 })
 
 test('inspect requires changing pool and singleThread/singleFork',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true})
+const{ stderr }=awaitrunVitest({inspect: true,maxWorkers: 4})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect cannot be used with multi-threading',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true,pool: 'threads',fileParallelism: true})
+const{ stderr }=awaitrunVitest({inspect: true,pool: 'threads',fileParallelism: true,maxWorkers: 4})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect in browser mode requires no-file-parallelism',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
+const{ stderr }=awaitrunVitest({inspect: true,maxWorkers: 4,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect-brk cannot be used with multi processing',async()=>{
-const{ stderr }=awaitrunVitest({inspect: true,pool: 'forks',fileParallelism: true})
+const{ stderr }=awaitrunVitest({inspect: true,pool: 'forks',fileParallelism: true,maxWorkers: 4})
 
 expect(stderr).toMatch('Error: You cannot use --inspect without "--no-file-parallelism"')
 })
 
 test('inspect-brk in browser mode requires no-file-parallelism',async()=>{
-const{ stderr }=awaitrunVitest({inspectBrk: true,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
+const{ stderr }=awaitrunVitest({inspectBrk: true,maxWorkers: 4,browser: {enabled: true,instances: [{browser: 'chromium'}],provider: playwright()}})
 
 expect(stderr).toMatch('Error: You cannot use --inspect-brk without "--no-file-parallelism"')
 })

packages/vitest/src/node/pool.ts

@@ -41,6 +41,7 @@ test('extended project inherits top-level pool related options', async () => {
 test('project level pool options overwrites top-level',async()=>{
 constconfig=awaitgetConfig({
 pool: 'vmForks',
+maxWorkers: 4,
 fileParallelism: true,
 projects: [{
 extends: true,
@@ -49,7 +50,7 @@ test('project level pool options overwrites top-level', async () => {
 })
 
 expect(config.pool).toBe('vmThreads')
-expect(config.fileParallelism).toBe(false)
+expect(config.maxWorkers).toBe(1)
 })
 
 test('isolated single worker pool receives single testfile at once',async()=>{
@@ -83,6 +84,24 @@ test('non-isolated single worker pool receives all testfiles at once', async ()
  `)
 })
 
+test('non-isolated happy-dom worker pool receives all testfiles at once',async()=>{
+constfiles=awaitgetConfig<string[]>({
+fileParallelism: false,
+isolate: false,
+environment: 'happy-dom',
+sequence: {sequencer: StableTestFileOrderSorter},
+},{include: ['print-testfiles.test.ts','a.test.ts','b.test.ts','c.test.ts']})
+
+expect(files.map(normalizeFilename)).toMatchInlineSnapshot(`
+ [
+ "<process-cwd>/fixtures/pool/a.test.ts",
+ "<process-cwd>/fixtures/pool/b.test.ts",
+ "<process-cwd>/fixtures/pool/c.test.ts",
+ "<process-cwd>/fixtures/pool/print-testfiles.test.ts",
+ ]
+ `)
+})
+
 asyncfunctiongetConfig<T=SerializedConfig>(options: Partial<TestUserConfig>,cliOptions: Partial<TestUserConfig>={}): Promise<T>{
 letconfig: T|undefined
 

packages/vitest/src/node/types/config.ts

@@ -36,9 +36,9 @@ export async function teardown() {
 
 try{
 assert.ok(results.success)
-assert.equal(results.numTotalTestSuites,24)
-assert.equal(results.numTotalTests,29)
-assert.equal(results.numPassedTests,29)
+assert.equal(results.numTotalTestSuites,20)
+assert.equal(results.numTotalTests,25)
+assert.equal(results.numPassedTests,25)
 assert.ok(results.coverageMap)
 
 constshared=results.testResults.filter((r: any)=>r.name.includes('space_shared/test.spec.ts'))