fix(jest-runtime, @jest/transform): allow V8 coverage provider to collect coverage from files which were not loaded explicitly

CHANGELOG.md

@@ -11,6 +11,7 @@
 - `[jest-message-util]` Add support for [AggregateError](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/AggregateError) ([#13946](https://github.com/facebook/jest/pull/13946) & [#13947](https://github.com/facebook/jest/pull/13947))
 - `[jest-message-util]` Add support for [Error causes](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/cause) in `test` and `it` ([#13935](https://github.com/facebook/jest/pull/13935) & [#13966](https://github.com/facebook/jest/pull/13966))
 - `[jest-reporters]` Add `summaryThreshold` option to summary reporter to allow overriding the internal threshold that is used to print the summary of all failed tests when the number of test suites surpasses it ([#13895](https://github.com/facebook/jest/pull/13895))
+- `[jest-runtime, @jest/transform]` Allow V8 coverage provider to collect coverage from files which were not loaded explicitly ([#13974](https://github.com/facebook/jest/pull/13974))
 - `[jest-snapshot]` Add support to `cts` and `mts` TypeScript files to inline snapshots ([#13975](https://github.com/facebook/jest/pull/13975))
 - `[jest-worker]` Add `start` method to worker farms ([#13937](https://github.com/facebook/jest/pull/13937))
 

e2e/__tests__/__snapshots__/coverageProviderV8.test.ts.snap

@@ -105,3 +105,12 @@ All files     |   59.37 |    33.33 |   33.33 |   59.37 |
  uncovered.js |       0 |        0 |       0 |       0 | 1-8               
 --------------|---------|----------|---------|---------|-------------------"
 `;
+
+exports[`vm script coverage generator 1`] = `
+"-------------|---------|----------|---------|---------|-------------------
+File         | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
+-------------|---------|----------|---------|---------|-------------------
+All files    |   88.88 |      100 |   66.66 |   88.88 |                   
+ vmscript.js |   88.88 |      100 |   66.66 |   88.88 | 20-22             
+-------------|---------|----------|---------|---------|-------------------"
+`;

e2e/__tests__/coverageProviderV8.test.ts

@@ -106,3 +106,15 @@ test('prints correct coverage report, if a TS module is transpiled by custom tra
   expect(exitCode).toBe(0);
   expect(stdout).toMatchSnapshot();
 });
+
+test('vm script coverage generator', () => {
+  const dir = path.resolve(__dirname, '../vmscript-coverage');
+  const {stdout, exitCode} = runJest(
+    dir,
+    ['--coverage', '--coverage-provider', 'v8'],
+    {stripAnsi: true},
+  );
+
+  expect(exitCode).toBe(0);
+  expect(stdout).toMatchSnapshot();
+});

e2e/vmscript-coverage/__tests__/extract-coverage.test.js

@@ -0,0 +1,42 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+const fs = require('fs');
+const path = require('path');
+const vm = require('vm');
+const filePath = path.resolve(__dirname, '../package/vmscript.js');
+
+test('extract coverage', () => {
+  const content = fs.readFileSync(filePath, {encoding: 'utf8'});
+
+  const case1 = vm.runInNewContext(
+    content,
+    {
+      inputObject: {
+        number: 0,
+      },
+    },
+    {
+      filename: filePath,
+    },
+  );
+
+  const case2 = vm.runInNewContext(
+    content,
+    {
+      inputObject: {
+        number: 7,
+      },
+    },
+    {
+      filename: filePath,
+    },
+  );
+
+  expect(case1).toBe(false);
+  expect(case2).toBe(true);
+});

e2e/vmscript-coverage/package.json

@@ -0,0 +1,9 @@
+{
+  "jest": {
+    "rootDir": "./",
+    "testEnvironment": "node",
+    "collectCoverageFrom": [
+      "package/**/*.js"
+    ]
+  }
+}

e2e/vmscript-coverage/package/vmscript.js

@@ -0,0 +1,27 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+function addOne(inputNumber) {
+  return ++inputNumber;
+}
+
+function isEven(inputNumber) {
+  if (inputNumber % 2 === 0) {
+    return true;
+  } else {
+    return false;
+  }
+}
+
+function notCovered() {
+  return 'not covered';
+}
+
+/* global inputObject */
+if (inputObject.number / 1 === inputObject.number) {
+  isEven(addOne(inputObject.number));
+}

packages/jest-runtime/src/index.ts

@@ -1267,8 +1267,12 @@ export default class Runtime {
         res =>
           // TODO: will this work on windows? It might be better if `shouldInstrument` deals with it anyways
           res.url.startsWith(this._config.rootDir) &&
-          this._v8CoverageSources!.has(res.url) &&
-          shouldInstrument(res.url, this._coverageOptions, this._config),
+          shouldInstrument(
+            res.url,
+            this._coverageOptions,
+            this._config,
+            /* loadedFilenames */ Array.from(this._v8CoverageSources!.keys()),
+          ),
       )
       .map(result => {
         const transformedFile = this._v8CoverageSources!.get(result.url);

packages/jest-transform/src/__tests__/shouldInstrument.test.ts

@@ -24,11 +24,13 @@ describe('shouldInstrument', () => {
       filename = defaultFilename,
       options: Partial<Options>,
       config: Partial<Config.ProjectConfig>,
+      loadedFilenames?: Array<string>,
     ) => {
       const result = shouldInstrument(
         filename,
         {...defaultOptions, ...options},
         {...defaultConfig, ...config},
+        loadedFilenames,
       );
       expect(result).toBe(true);
     };
@@ -99,18 +101,38 @@ describe('shouldInstrument', () => {
         testRegex: ['.*\\.(test)\\.(js)$'],
       });
     });
+
+    it('when file is in loadedFilenames list', () => {
+      testShouldInstrument(
+        'do/collect/coverage.js',
+        defaultOptions,
+        defaultConfig,
+        ['do/collect/coverage.js'],
+      );
+    });
+
+    it('when file is in not loadedFilenames list, but matches collectCoverageFrom', () => {
+      testShouldInstrument(
+        'do/collect/coverage.js',
+        {collectCoverageFrom: ['!**/dont/**/*.js', '**/do/**/*.js']},
+        defaultConfig,
+        ['dont/collect/coverage.js'],
+      );
+    });
   });
 
   describe('should return false', () => {
     const testShouldInstrument = (
       filename = defaultFilename,
       options: Partial<Options>,
       config: Partial<Config.ProjectConfig>,
+      loadedFilenames?: Array<string>,
     ) => {
       const result = shouldInstrument(
         filename,
         {...defaultOptions, ...options},
         {...defaultConfig, ...config},
+        loadedFilenames,
       );
       expect(result).toBe(false);
     };
@@ -205,5 +227,23 @@ describe('shouldInstrument', () => {
         setupFilesAfterEnv: ['setupTest.js'],
       });
     });
+
+    it('when file is not in loadedFilenames list', () => {
+      testShouldInstrument(
+        'dont/collect/coverage.js',
+        defaultOptions,
+        defaultConfig,
+        ['do/collect/coverage.js'],
+      );
+    });
+
+    it('when file is in not loadedFilenames list and does not match collectCoverageFrom', () => {
+      testShouldInstrument(
+        'dont/collect/coverage.js',
+        {collectCoverageFrom: ['!**/dont/**/*.js', '**/do/**/*.js']},
+        defaultConfig,
+        ['do/collect/coverage.js'],
+      );
+    });
   });
 });

packages/jest-transform/src/shouldInstrument.ts

@@ -34,6 +34,7 @@ export default function shouldInstrument(
   filename: string,
   options: ShouldInstrumentOptions,
   config: Config.ProjectConfig,
+  loadedFilenames?: Array<string>,
 ): boolean {
   if (!options.collectCoverage) {
     return false;
@@ -60,6 +61,14 @@ export default function shouldInstrument(
     }
   }
 
+  if (
+    options.collectCoverageFrom.length === 0 &&
+    loadedFilenames != null &&
+    !loadedFilenames.includes(filename)
+  ) {
+    return false;
+  }
+
   if (
     // still cover if `only` is specified
     options.collectCoverageFrom.length &&