feat: support istanbul coverage provider (#1676)

Co-authored-by: Anthony Fu <anthonyfu117@hotmail.com>

.eslintignore

@@ -5,4 +5,4 @@ node_modules
 *.d.ts
 coverage
 !.vitepress
-test/core/src/self
+test/core/src/self

.gitignore

@@ -5,6 +5,7 @@ yarn-debug.log*
 yarn-error.log*
 lib-cov
 coverage
+!**/integrations/coverage
 node_modules
 .env
 .cache

README.md

@@ -35,7 +35,7 @@ A blazing fast unit test framework powered by Vite.
 - [Jest Snapshot](https://jestjs.io/docs/snapshot-testing)
 - [Chai](https://www.chaijs.com/) built-in for assertions, with [Jest expect](https://jestjs.io/docs/expect) compatible APIs.
 - [Smart & instant watch mode](https://vitest.dev/guide/features.html#watch-mode), like HMR for tests!
-- [Native code coverage](https://vitest.dev/guide/features.html#coverage) via [c8](https://github.com/bcoe/c8)
+- [Native code coverage](https://vitest.dev/guide/features.html#coverage) via [c8](https://github.com/bcoe/c8) or [`istanbul`](https://istanbul.js.org/).
 - [Tinyspy](https://github.com/Aslemammad/tinyspy) built-in for mocking, stubbing, and spies.
 - [JSDOM](https://github.com/jsdom/jsdom) and [happy-dom](https://github.com/capricorn86/happy-dom) for DOM and browser API mocking
 - Components testing ([Vue](./examples/vue), [React](./examples/react), [Svelte](./examples/svelte), [Lit](./examples/lit), [Vitesse](./examples/vitesse))

docs/.vitepress/components/FeaturesList.vue

@@ -20,7 +20,7 @@
     <ListItem><a target="_blank" href="https://www.chaijs.com/" rel="noopener noreferrer">Chai</a> built-in for assertions + <a target="_blank" href="https://jestjs.io/docs/expect" rel="noopener noreferrer">Jest expect</a> compatible APIs</ListItem>
     <ListItem><a target="_blank" href="https://github.com/Aslemammad/tinyspy" rel="noopener noreferrer">Tinyspy</a> built-in for mocking</ListItem>
     <ListItem><a target="_blank" href="https://github.com/capricorn86/happy-dom" rel="noopener noreferrer">happy-dom</a> or <a target="_blank" href="https://github.com/jsdom/jsdom" rel="noopener noreferrer">jsdom</a> for DOM mocking</ListItem>
-    <ListItem>Native code coverage via <a target="_blank" href="https://github.com/bcoe/c8" rel="noopener noreferrer">c8</a></ListItem>
+    <ListItem>Code coverage via <a target="_blank" href="https://github.com/bcoe/c8" rel="noopener noreferrer">c8</a> or <a target="_blank" href="https://istanbul.js.org/" rel="noopener noreferrer">istanbul</a></ListItem>
     <ListItem>Rust-like <a href="/guide/in-source">in-source testing</a></ListItem>
   </ul>
 </template>

docs/config/index.md

@@ -420,10 +420,103 @@ Isolate environment for each test file. Does not work if you disable [`--threads
 
 ### coverage
 
-- **Type:** `C8Options`
+- **Type:** `CoverageC8Options | CoverageIstanbulOptions`
 - **Default:** `undefined`
 
-Coverage options passed to [C8](https://github.com/bcoe/c8).
+You can use [`c8`](https://github.com/bcoe/c8) or [`istanbul`](https://istanbul.js.org/) for coverage collection.
+
+#### provider
+
+- **Type:** `'c8' | 'istanbul'`
+- **Default:** `'c8'`
+
+Use `provider` to select the tool for coverage collection.
+
+#### CoverageC8Options
+
+Used when `provider: 'c8'` is set. Coverage options are passed to [`c8`](https://github.com/bcoe/c8).
+
+#### CoverageIstanbulOptions
+
+Used when `provider: 'istanbul'` is set.
+
+##### exclude
+
+- **Type:** `string[]`
+- **Default:** `[]`
+
+List of files excluded from coverage as glob patterns.
+
+##### skipFull
+
+- **Type:** `boolean`
+- **Default:** `false`
+
+Do not show files with 100% statement, branch, and function coverage.
+
+##### perFile
+
+- **Type:** `boolean`
+- **Default:** `false`
+
+Check thresholds per file.
+
+##### lines
+
+- **Type:** `number`
+
+Threshold for lines.
+
+##### functions
+
+- **Type:** `number`
+
+Threshold for functions.
+
+##### branches
+
+- **Type:** `number`
+
+Threshold for branches.
+
+##### statements
+
+- **Type:** `number`
+
+Threshold for statements.
+
+##### ignoreClassMethods
+
+- **Type:** `string[]`
+- **Default:** []
+
+Set to array of class method names to ignore for coverage.
+
+##### watermarks
+
+- **Type:**
+<!-- eslint-skip -->
+```ts
+{
+  statements?: [number, number],
+  functions?: [number, number],
+  branches?: [number, number],
+  lines?: [number, number]
+}
+```
+
+- **Default:**
+<!-- eslint-skip -->
+```ts
+{
+  statements: [50, 80],
+  functions: [50, 80],
+  branches: [50, 80],
+  lines: [50, 80]
+}
+```
+
+Watermarks for statements, lines, branches and functions.
 
 ### testNamePattern
 

docs/guide/cli.md

@@ -61,7 +61,7 @@ vitest related /src/index.ts /src/hello-world.js
 | `--outputTruncateLength <length>` | Truncate output diff lines up to `<length>` number of characters. |
 | `--outputDiffLines <lines>` | Limit number of output diff lines up to `<lines>`. |
 | `--outputFile <filename/-s>` | Write test results to a file when the `--reporter=json` or `--reporter=junit` option is also specified <br /> Via [cac's dot notation] you can specify individual outputs for multiple reporters |
-| `--coverage` | Use c8 for coverage |
+| `--coverage` | Enable coverage report |
 | `--run` | Do not watch |
 | `--mode` | Override Vite mode (default: `test`) |
 | `--mode <name>` | Override Vite mode (default: `test`) |

docs/guide/coverage.md

@@ -4,13 +4,46 @@ title: Coverage | Guide
 
 # Coverage
 
-Vitest supports Native code coverage via [`c8`](https://github.com/bcoe/c8). `c8` is an optional peer dependency, to use the coverage feature you will need to install it first by:
+Vitest supports Native code coverage via [`c8`](https://github.com/bcoe/c8) and instrumented code coverage via [`istanbul`](https://istanbul.js.org/).
+
+## Coverage Providers
+
+:::tip
+Since Vitest v0.22.0
+:::
+
+Both `c8` and `istanbul` support are optional. By default, `c8` will be used.
+
+You can select the coverage tool by setting `test.coverage.provider` to either `c8` or `istanbul`:
+
+```ts
+// vite.config.ts
+import { defineConfig } from 'vitest/config'
+
+export default defineConfig({
+  test: {
+    coverage: {
+      provider: 'istanbul' // or 'c8'
+    },
+  },
+})
+```
+
+When you start the Vitest process, it will prompt you to install the corresponding support package automatically.
+
+Or if you prefer to install them manually:
 
 ```bash
-npm i -D c8
+# For c8
+npm i -D @vitest/coverage-c8
+
+# For istanbul
+npm i -D @vitest/coverage-istanbul
 ```
 
-Then you could get the coverage by passing the `--coverage` flag in CLI.
+## Coverage Setup
+
+To test with coverage enabled, you can pass the `--coverage` flag in CLI.
 
 ```json
 {
@@ -35,3 +68,23 @@ export default defineConfig({
   },
 })
 ```
+
+## Custom Coverage Provider
+
+It's also possible to provide your custom coverage provider by passing an object to the `test.coverage.provider`:
+
+```ts
+// vite.config.ts
+import { defineConfig } from 'vitest/config'
+import CustomCoverageProvider from 'my-custom-coverage-provider'
+
+export default defineConfig({
+  test: {
+    coverage: {
+      provider: CustomCoverageProvider()
+    },
+  },
+})
+```
+
+Please refer to the type definition for more details.

docs/guide/features.md

@@ -136,7 +136,7 @@ Learn more at [Mocking](/guide/mocking).
 
 ## Coverage
 
-Vitest supports Native code coverage via [c8](https://github.com/bcoe/c8).
+Vitest supports Native code coverage via [`c8`](https://github.com/bcoe/c8) and instrumented code coverage via [`istanbul`](https://istanbul.js.org/).
 
 ```json
 {
@@ -147,20 +147,7 @@ Vitest supports Native code coverage via [c8](https://github.com/bcoe/c8).
 }
 ```
 
-To configure it, set `test.coverage` options in your config file:
-
-```ts
-// vite.config.ts
-import { defineConfig } from 'vitest/config'
-
-export default defineConfig({
-  test: {
-    coverage: {
-      reporter: ['text', 'json', 'html'],
-    },
-  },
-})
-```
+Learn more at [Coverage](/guide/coverage).
 
 ## In-source testing
 

package.json

@@ -42,6 +42,8 @@
     "@types/node": "^18.7.3",
     "@types/ws": "^8.5.3",
     "@vitest/browser": "workspace:*",
+    "@vitest/coverage-c8": "workspace:*",
+    "@vitest/coverage-istanbul": "workspace:*",
     "@vitest/ui": "workspace:*",
     "bumpp": "^8.2.1",
     "c8": "^7.12.0",
@@ -64,6 +66,7 @@
     "rollup-plugin-esbuild": "^4.9.3",
     "rollup-plugin-license": "^2.8.1",
     "simple-git-hooks": "^2.8.0",
+    "tsup": "^6.2.2",
     "typescript": "^4.7.4",
     "vite": "^3.0.7",
     "vitest": "workspace:*",

packages/coverage-c8/package.json

@@ -0,0 +1,50 @@
+{
+  "name": "@vitest/coverage-c8",
+  "type": "module",
+  "version": "0.0.0",
+  "description": "C8 coverage provider for Vitest",
+  "author": "Anthony Fu <anthonyfu117@hotmail.com>",
+  "license": "MIT",
+  "funding": "https://github.com/sponsors/antfu",
+  "homepage": "https://github.com/vitest-dev/vitest#readme",
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/vitest-dev/vitest.git",
+    "directory": "packages/coverage-c8"
+  },
+  "bugs": {
+    "url": "https://github.com/vitest-dev/vitest/issues"
+  },
+  "keywords": [
+    "vite",
+    "vitest",
+    "test",
+    "coverage",
+    "c8"
+  ],
+  "sideEffects": false,
+  "exports": {
+    ".": {
+      "types": "./dist/index.d.ts",
+      "import": "./dist/index.js"
+    },
+    "./*": "./*"
+  },
+  "main": "./dist/index.js",
+  "module": "./dist/index.js",
+  "types": "./dist/index.d.ts",
+  "files": [
+    "dist"
+  ],
+  "scripts": {
+    "build": "rimraf dist && rollup -c",
+    "dev": "rollup -c --watch --watch.include=src/**"
+  },
+  "dependencies": {
+    "c8": "^7.12.0",
+    "vitest": "workspace:*"
+  },
+  "devDependencies": {
+    "vite-node": "workspace:*"
+  }
+}

packages/coverage-c8/rollup.config.js

@@ -0,0 +1,62 @@
+import { builtinModules } from 'module'
+import esbuild from 'rollup-plugin-esbuild'
+import dts from 'rollup-plugin-dts'
+import commonjs from '@rollup/plugin-commonjs'
+import json from '@rollup/plugin-json'
+import alias from '@rollup/plugin-alias'
+import nodeResolve from '@rollup/plugin-node-resolve'
+import { join } from 'pathe'
+import pkg from './package.json'
+
+const entries = {
+  index: 'src/index.ts',
+}
+
+const external = [
+  ...builtinModules,
+  ...Object.keys(pkg.dependencies || {}),
+  ...Object.keys(pkg.peerDependencies || {}),
+  'c8/lib/report.js',
+  'c8/lib/commands/check-coverage.js',
+  'vitest',
+  'vitest/node',
+  'vitest/config',
+]
+
+const plugins = [
+  alias({
+    entries: [
+      { find: /^node:(.+)$/, replacement: '$1' },
+    ],
+  }),
+  nodeResolve(),
+  json(),
+  commonjs(),
+  esbuild({
+    target: 'node14',
+  }),
+]
+
+export default () => [
+  {
+    input: entries,
+    output: {
+      dir: 'dist',
+      format: 'esm',
+    },
+    external,
+    plugins,
+  },
+  {
+    input: entries,
+    output: {
+      dir: join(process.cwd(), 'dist'),
+      entryFileNames: '[name].d.ts',
+      format: 'esm',
+    },
+    external,
+    plugins: [
+      dts({ respectExternal: true }),
+    ],
+  },
+]

packages/coverage-c8/src/index.ts

@@ -0,0 +1,6 @@
+export * from './takeCoverage'
+
+export async function getProvider() {
+  const { C8CoverageProvider } = await import('./provider')
+  return new C8CoverageProvider()
+}