fix(cache): preserve test results from previous runs (#8043)

Author: macko911

packages/vitest/src/node/cache/results.ts

@@ -45,8 +45,9 @@ export class ResultsCache {
 
     const resultsCache = await fs.promises.readFile(this.cachePath, 'utf8')
     const { results, version } = JSON.parse(resultsCache || '[]')
+    const [major, minor] = version.split('.')
     // handling changed in 0.30.0
-    if (Number(version.split('.')[1]) >= 30) {
+    if (major > 0 || Number(minor) >= 30) {
       this.cache = new Map(results)
       this.version = version
       results.forEach(([spec]: [string]) => {

test/config/fixtures/cache/second.test.ts

@@ -0,0 +1,5 @@
+import { expect, test } from "vitest";
+
+test('', () => {
+  expect(true).toBe(true)
+})

test/config/test/cache.test.ts

@@ -1,3 +1,4 @@
+import { readFileSync } from 'node:fs'
 import { resolve } from 'pathe'
 import { describe, expect, test } from 'vitest'
 import { runVitest } from '../../test-utils'
@@ -57,6 +58,31 @@ test('use cacheDir', async () => {
   expect(cachePath).toMatch(path)
 })
 
+test('preserves previous test results', async () => {
+  const firstRun = await runVitest({
+    root,
+    include: ['basic.test.ts'],
+  })
+
+  expect(firstRun.stdout).toContain('✓ basic.test.ts >')
+  expect(firstRun.stderr).toBe('')
+
+  const cachePath = firstRun.ctx!.cache.results.getCachePath()
+  const firstRunCacheContent = readFileSync(cachePath!, 'utf-8')
+  expect(firstRunCacheContent).toContain('basic.test.ts')
+
+  const secondRun = await runVitest({
+    root,
+    include: ['second.test.ts'],
+  })
+  expect(secondRun.stdout).toContain('✓ second.test.ts >')
+  expect(secondRun.stderr).toBe('')
+
+  const secondRunCacheContent = readFileSync(cachePath!, 'utf-8')
+  expect(secondRunCacheContent).toContain('basic.test.ts')
+  expect(secondRunCacheContent).toContain('second.test.ts')
+})
+
 describe('with optimizer enabled', () => {
   const deps = {
     optimizer: {