[READ-ONLY] Mirror of https://github.com/vitest-dev/vitest. Next generation testing framework powered by Vite.
vitest.dev
test
testing-tools
vite
fix(coverage): expose profiling timers (#7820)
authored by
Ari Perkkiö
and committed by
GitHub
(Apr 11, 2025, 8:24 AM +0300)
5652bf92
b1942636
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docs/guide/coverage.md
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docs/guide/coverage.md
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To see all configurable options for coverage, see the [coverage Config Reference](https://vitest.dev/config/#coverage).
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## Coverage performance
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If code coverage generation is slow on your project, see [Profiling Test Performance | Code coverage](/guide/profiling-test-performance.html#code-coverage).
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## Vitest UI
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You can check your coverage report in [Vitest UI](/guide/ui).
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docs/guide/profiling-test-performance.md
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docs/guide/profiling-test-performance.md
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_src_prime-number_ts-525172412.js
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```
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## Code coverage
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If code coverage generation is slow on your project you can use `DEBUG=vitest:coverage` environment variable to enable performance logging.
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```bash
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$ DEBUG=vitest:coverage vitest --run --coverage
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RUN v3.1.1 /x/vitest-example
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vitest:coverage Reading coverage results 2/2
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vitest:coverage Converting 1/2
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vitest:coverage 4 ms /x/src/multiply.ts
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vitest:coverage Converting 2/2
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vitest:coverage 552 ms /x/src/add.ts
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vitest:coverage Uncovered files 1/2
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vitest:coverage File "/x/src/large-file.ts" is taking longer than 3s # [!code error]
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vitest:coverage 3027 ms /x/src/large-file.ts
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vitest:coverage Uncovered files 2/2
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vitest:coverage 4 ms /x/src/untested-file.ts
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vitest:coverage Generate coverage total time 3521 ms
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```
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This profiling approach is great for detecting large files that are accidentally picked by coverage providers.
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For example if your configuration is accidentally including large built minified Javascript files in code coverage, they should appear in logs.
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In these cases you might want to adjust your [`coverage.include`](/config/#coverage-include) and [`coverage.exclude`](/config/#coverage-exclude) options.
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## Inspecting profiling records
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You can inspect the contents of `*.cpuprofile` and `*.heapprofile` with various tools. See list below for examples.
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packages/coverage-istanbul/src/provider.ts
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packages/coverage-istanbul/src/provider.ts
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}
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async generateCoverage({ allTestsRun }: ReportContext): Promise<CoverageMap> {
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const start = debug.enabled ? performance.now() : 0
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const coverageMap = this.createCoverageMap()
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let coverageMapByTransformMode = this.createCoverageMap()
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···
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if (this.options.excludeAfterRemap) {
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coverageMap.filter(filename => this.testExclude.shouldInstrument(filename))
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}
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if (debug.enabled) {
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debug('Generate coverage total time %d ms', (performance.now() - start!).toFixed())
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}
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return coverageMap
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// Note that these cannot be run parallel as synchronous instrumenter.lastFileCoverage
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// returns the coverage of the last transformed file
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for (const [index, filename] of uncoveredFiles.entries()) {
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debug('Uncovered file %s %d/%d', filename, index, uncoveredFiles.length)
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let timeout: ReturnType<typeof setTimeout> | undefined
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let start: number | undefined
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if (debug.enabled) {
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start = performance.now()
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timeout = setTimeout(() => debug(c.bgRed(`File "${filename}" is taking longer than 3s`)), 3_000)
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debug('Uncovered file %d/%d', index, uncoveredFiles.length)
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}
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// Make sure file is not served from cache so that instrumenter loads up requested file coverage
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await transform(`${filename}?v=${cacheKey}`)
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const lastCoverage = this.instrumenter.lastFileCoverage()
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coverageMap.addFileCoverage(lastCoverage)
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if (debug.enabled) {
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clearTimeout(timeout)
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const diff = performance.now() - start!
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const color = diff > 500 ? c.bgRed : c.bgGreen
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debug(`${color(` ${diff.toFixed()} ms `)} ${filename}`)
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}
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}
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return coverageMap
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packages/coverage-v8/src/provider.ts
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packages/coverage-v8/src/provider.ts
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}
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async generateCoverage({ allTestsRun }: ReportContext): Promise<CoverageMap> {
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const start = debug.enabled ? performance.now() : 0
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const coverageMap = this.createCoverageMap()
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let merged: RawCoverage = { result: [] }
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···
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if (this.options.excludeAfterRemap) {
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coverageMap.filter(filename => this.testExclude.shouldInstrument(filename))
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}
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if (debug.enabled) {
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debug(`Generate coverage total time ${(performance.now() - start!).toFixed()} ms`)
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}
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return coverageMap
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}
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await Promise.all(chunk.map(async (filename) => {
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let timeout: ReturnType<typeof setTimeout> | undefined
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let start: number | undefined
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if (debug.enabled) {
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start = performance.now()
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timeout = setTimeout(() => debug(c.bgRed(`File "${filename.pathname}" is taking longer than 3s`)), 3_000)
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}
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const sources = await this.getSources(
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filename.href,
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transformResults,
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}
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coverageMap.merge(converter.toIstanbul())
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if (debug.enabled) {
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clearTimeout(timeout)
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const diff = performance.now() - start!
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const color = diff > 500 ? c.bgRed : c.bgGreen
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debug(`${color(` ${diff.toFixed()} ms `)} ${filename.pathname}`)
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}
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}))
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}
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···
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await Promise.all(
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chunk.map(async ({ url, functions, startOffset }) => {
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let timeout: ReturnType<typeof setTimeout> | undefined
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let start: number | undefined
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if (debug.enabled) {
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start = performance.now()
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timeout = setTimeout(() => debug(c.bgRed(`File "${fileURLToPath(url)}" is taking longer than 3s`)), 3_000)
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}
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const sources = await this.getSources(
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url,
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transformResults,
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}
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coverageMap.merge(converter.toIstanbul())
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if (debug.enabled) {
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clearTimeout(timeout)
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const diff = performance.now() - start!
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const color = diff > 500 ? c.bgRed : c.bgGreen
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debug(`${color(` ${diff.toFixed()} ms `)} ${fileURLToPath(url)}`)
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}
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}),
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)
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}
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packages/vitest/src/node/coverage.ts
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packages/vitest/src/node/coverage.ts
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for (const chunk of this.toSlices(filenames, this.options.processingConcurrency)) {
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if (onDebug.enabled) {
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index += chunk.length
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onDebug('Covered files %d/%d', index, total)
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onDebug(`Reading coverage results ${index}/${total}`)
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}
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await Promise.all(chunk.map(async (filename) => {