fix(watch): run test files when added to filesystem

packages/vitest/src/node/core.ts

@@ -592,6 +592,8 @@ export class Vitest {
       id = slash(id)
       updateLastChanged(id)
       if (await this.isTargetFile(id)) {
+        this.projectsTestFiles.set(id, new Set(this.projects))
+
         this.changedTests.add(id)
         this.scheduleRerun([id])
       }

test/watch/test/file-watching.test.ts

@@ -1,4 +1,4 @@
-import { readFileSync, writeFileSync } from 'node:fs'
+import { readFileSync, rmSync, writeFileSync } from 'node:fs'
 import { afterEach, describe, test } from 'vitest'
 
 import { startWatchMode } from './utils'
@@ -12,6 +12,8 @@ const testFileContent = readFileSync(testFile, 'utf-8')
 const configFile = 'fixtures/vitest.config.ts'
 const configFileContent = readFileSync(configFile, 'utf-8')
 
+const cleanups: (() => void)[] = []
+
 function editFile(fileContent: string) {
   return `// Modified by file-watching.test.ts
 ${fileContent}
@@ -23,6 +25,7 @@ afterEach(() => {
   writeFileSync(sourceFile, sourceFileContent, 'utf8')
   writeFileSync(testFile, testFileContent, 'utf8')
   writeFileSync(configFile, configFileContent, 'utf8')
+  cleanups.splice(0).forEach(cleanup => cleanup())
 })
 
 test('editing source file triggers re-run', async () => {
@@ -64,6 +67,26 @@ test('editing config file reloads new changes', async () => {
   await vitest.waitForOutput('ok 2')
 })
 
+test('adding a new test file triggers re-run', async () => {
+  const vitest = await startWatchMode()
+
+  const testFile = 'fixtures/new-dynamic.test.ts'
+  const testFileContent = `
+import { expect, test } from "vitest";
+
+test("dynamic test case", () => {
+  console.log("Running added dynamic test")
+  expect(true).toBeTruthy()
+})
+`
+  cleanups.push(() => rmSync(testFile))
+  writeFileSync(testFile, testFileContent, 'utf-8')
+
+  await vitest.waitForOutput('Running added dynamic test')
+  await vitest.waitForOutput('RERUN  ../new-dynamic.test.ts')
+  await vitest.waitForOutput('1 passed')
+})
+
 describe('browser', () => {
   test.runIf((process.platform !== 'win32'))('editing source file triggers re-run', async () => {
     const vitest = await startWatchMode('--browser.enabled', '--browser.headless', '--browser.name=chrome')

test/watch/test/workspaces.test.ts

@@ -1,13 +1,14 @@
 import { fileURLToPath } from 'node:url'
-import { readFileSync, writeFileSync } from 'node:fs'
-import { afterAll, it } from 'vitest'
+import { readFileSync, rmSync, writeFileSync } from 'node:fs'
+import { afterAll, afterEach, expect, it } from 'vitest'
 import { dirname, resolve } from 'pathe'
 import { startWatchMode } from './utils'
 
 const file = fileURLToPath(import.meta.url)
 const dir = dirname(file)
 const root = resolve(dir, '..', '..', 'workspaces')
 const config = resolve(root, 'vitest.config.ts')
+const cleanups: (() => void)[] = []
 
 const srcMathFile = resolve(root, 'src', 'math.ts')
 const specSpace2File = resolve(root, 'space_2', 'test', 'node.spec.ts')
@@ -27,6 +28,10 @@ function startVitest() {
   )
 }
 
+afterEach(() => {
+  cleanups.splice(0).forEach(cleanup => cleanup())
+})
+
 afterAll(() => {
   writeFileSync(srcMathFile, srcMathContent, 'utf8')
   writeFileSync(specSpace2File, specSpace2Content, 'utf8')
@@ -65,3 +70,30 @@ it('filters by test name inside a workspace', async () => {
   await vitest.waitForOutput('Test name pattern: /2 x 2 = 4/')
   await vitest.waitForOutput('Test Files  1 passed')
 })
+
+it('adding a new test file triggers re-run', async () => {
+  const vitest = await startVitest()
+
+  const testFile = resolve(root, 'space_2', 'test', 'new-dynamic.test.ts')
+  const testFileContent = `
+import { expect, test } from "vitest";
+
+test("dynamic test case", () => {
+  console.log("Running added dynamic test")
+  expect(true).toBeTruthy()
+})
+`
+  cleanups.push(() => rmSync(testFile))
+  writeFileSync(testFile, testFileContent, 'utf-8')
+
+  // Wait for tests to end
+  await vitest.waitForOutput('Waiting for file changes')
+
+  await vitest.waitForOutput('Running added dynamic test')
+  await vitest.waitForOutput('RERUN  space_2/test/new-dynamic.test.ts')
+  await vitest.waitForOutput('|space_2| test/new-dynamic.test.ts')
+
+  // Test case should not be run by other projects
+  expect(vitest.output).not.include('|space_1| ../space_2/test/new-dynamic.test.ts')
+  expect(vitest.output).not.include('|space_3| ../space_2/test/new-dynamic.test.ts')
+})