From 3c851872f88ff2fd6adcfcd529ee1771422aaa7d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ari=20Perkki=C3=B6?= <ari.perkkio@gmail.com>
Date: Fri, 28 Jul 2023 13:29:46 +0300
Subject: [PATCH] fix(coverage): exclude vite virtual modules by default
 (#3794)

---
 docs/config/index.md                          |  3 +++
 packages/vitest/src/defaults.ts               |  3 +++
 .../generic.report.test.ts                    | 16 +++++++++++
 test/coverage-test/test/coverage.test.ts      | 12 +++++++++
 test/coverage-test/vitest.config.ts           | 27 +++++++++++++++++++
 5 files changed, 61 insertions(+)

diff --git a/docs/config/index.md b/docs/config/index.md
index f3028ada12fb..73131c2c866c 100644
--- a/docs/config/index.md
+++ b/docs/config/index.md
@@ -723,6 +723,9 @@ List of files included in coverage as glob patterns
   'dist/**',
   'packages/*/test?(s)/**',
   '**/*.d.ts',
+  '**/virtual:*',
+  '**/__x00__*',
+  '**/\x00*',
   'cypress/**',
   'test?(s)/**',
   'test?(-*).?(c|m)[jt]s?(x)',
diff --git a/packages/vitest/src/defaults.ts b/packages/vitest/src/defaults.ts
index 10040a9486dc..2f80f9e85321 100644
--- a/packages/vitest/src/defaults.ts
+++ b/packages/vitest/src/defaults.ts
@@ -15,6 +15,9 @@ const defaultCoverageExcludes = [
   'dist/**',
   'packages/*/test?(s)/**',
   '**/*.d.ts',
+  '**/virtual:*',
+  '**/__x00__*',
+  '**/\x00*',
   'cypress/**',
   'test?(s)/**',
   'test?(-*).?(c|m)[jt]s?(x)',
diff --git a/test/coverage-test/coverage-report-tests/generic.report.test.ts b/test/coverage-test/coverage-report-tests/generic.report.test.ts
index c9b62ddce129..350c23c3677e 100644
--- a/test/coverage-test/coverage-report-tests/generic.report.test.ts
+++ b/test/coverage-test/coverage-report-tests/generic.report.test.ts
@@ -101,3 +101,19 @@ test('coverage provider does not conflict with built-in reporter\'s outputFile',
 
   expect(files).toContain('junit.xml')
 })
+
+test('virtual files should be excluded', () => {
+  const files = fs.readdirSync(resolve('./coverage'))
+  const srcFiles = fs.readdirSync(resolve('./coverage/src'))
+
+  for (const file of [...files, ...srcFiles]) {
+    expect(file).not.toContain('virtual:')
+
+    // Vitest in node
+    expect(file).not.toContain('__x00__')
+    expect(file).not.toContain('\0')
+
+    // Vitest browser
+    expect(file).not.toContain('\x00')
+  }
+})
diff --git a/test/coverage-test/test/coverage.test.ts b/test/coverage-test/test/coverage.test.ts
index 6d3e20f399a3..fcf719945215 100644
--- a/test/coverage-test/test/coverage.test.ts
+++ b/test/coverage-test/test/coverage.test.ts
@@ -1,9 +1,16 @@
 import { expect, test } from 'vitest'
+
+// @ts-expect-error -- untyped virtual file provided by custom plugin
+import virtualFile1 from 'virtual:vitest-custom-virtual-file-1'
+
 import { implicitElse } from '../src/implicitElse'
 import { useImportEnv } from '../src/importEnv'
 import { second } from '../src/function-count'
 import { runDynamicFileCJS, runDynamicFileESM } from '../src/dynamic-files'
 
+// @ts-expect-error -- untyped virtual file provided by custom plugin
+import virtualFile2 from '\0vitest-custom-virtual-file-2'
+
 // Browser mode crashes with dynamic files. Enable this when browser mode works.
 // To keep istanbul report consistent between browser and node, skip dynamic tests when istanbul is used.
 const skipDynamicFiles = globalThis.process?.env.COVERAGE_PROVIDER === 'istanbul' || !globalThis.process?.env.COVERAGE_PROVIDER
@@ -40,3 +47,8 @@ test.skipIf(skipDynamicFiles)('run dynamic ESM file', async () => {
 test.skipIf(skipDynamicFiles)('run dynamic CJS file', async () => {
   await runDynamicFileCJS()
 })
+
+test('virtual file imports', () => {
+  expect(virtualFile1).toBe('This file should be excluded from coverage report #1')
+  expect(virtualFile2).toBe('This file should be excluded from coverage report #2')
+})
diff --git a/test/coverage-test/vitest.config.ts b/test/coverage-test/vitest.config.ts
index 0eb103425292..258ea5e8bf7b 100644
--- a/test/coverage-test/vitest.config.ts
+++ b/test/coverage-test/vitest.config.ts
@@ -7,6 +7,33 @@ const provider = process.argv[1 + process.argv.indexOf('--provider')]
 export default defineConfig({
   plugins: [
     vue(),
+    {
+      // Simulates Vite's virtual files: https://vitejs.dev/guide/api-plugin.html#virtual-modules-convention
+      name: 'vitest-custom-virtual-files',
+      resolveId(id) {
+        if (id === 'virtual:vitest-custom-virtual-file-1')
+          return 'src/virtual:vitest-custom-virtual-file-1.ts'
+
+        if (id === '\0vitest-custom-virtual-file-2')
+          return 'src/\0vitest-custom-virtual-file-2.ts'
+      },
+      load(id) {
+        if (id === 'src/virtual:vitest-custom-virtual-file-1.ts') {
+          return `
+            const virtualFile = "This file should be excluded from coverage report #1"
+            export default virtualFile;
+          `
+        }
+
+        // Vitest browser resolves this as "\x00", Node as "__x00__"
+        if (id === 'src/__x00__vitest-custom-virtual-file-2.ts' || id === 'src/\x00vitest-custom-virtual-file-2.ts') {
+          return `
+            const virtualFile = "This file should be excluded from coverage report #2"
+            export default virtualFile;
+          `
+        }
+      },
+    },
   ],
   define: {
     MY_CONSTANT: '"my constant"',