fix: make coverage work when using projects option

Author: ahnpnl

CHANGELOG.md

@@ -10,6 +10,7 @@
 - `[jest-reporters]` Fix issue where console output not displayed for GHA reporter even with `silent: false` option ([#15864](https://github.com/jestjs/jest/pull/15864))
 - `[jest-runtime]` Fix issue where user cannot utilize dynamic import despite specifying `--experimental-vm-modules` Node option ([#15842](https://github.com/jestjs/jest/pull/15842))
 - `[jest-test-sequencer]` Fix issue where failed tests due to compilation errors not getting re-executed even with `--onlyFailures` CLI option ([#15851](https://github.com/jestjs/jest/pull/15851))
+- `[jest-runner, jest-transform]` Fix coverage report doesn't show correct code coverage when using `projects` config option ([#15880](https://github.com/jestjs/jest/pull/15880)), fixes ([#5417](https://github.com/jestjs/jest/issues/5417))
 
 ### Chore & Maintenance
 

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

@@ -138,3 +138,15 @@ Functions    : 50% ( 3/6 )
 Lines        : 60% ( 12/20 )
 ================================================================================"
 `;
+
+exports[`outputs coverage report with projects option 1`] = `
+"------------|---------|----------|---------|---------|-------------------
+File        | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
+------------|---------|----------|---------|---------|-------------------
+All files   |   66.66 |      100 |      50 |   66.66 |                   
+ client     |   66.66 |      100 |      50 |   66.66 |                   
+  client.js |   66.66 |      100 |      50 |   66.66 | 13                
+ server     |   66.66 |      100 |      50 |   66.66 |                   
+  server.js |   66.66 |      100 |      50 |   66.66 | 13                
+------------|---------|----------|---------|---------|-------------------"
+`;

e2e/__tests__/coverageReport.test.ts

@@ -189,3 +189,13 @@ test('generates coverage when using the testRegex config param ', () => {
   expect(stdout).toMatchSnapshot();
   expect(exitCode).toBe(0);
 });
+
+test('outputs coverage report with projects option', () => {
+  const projectDir = path.resolve(__dirname, '../coverage-with-projects');
+  const {stdout, exitCode} = runJest(projectDir, ['--no-cache', '--coverage'], {
+    stripAnsi: true,
+  });
+
+  expect(stdout).toMatchSnapshot();
+  expect(exitCode).toBe(0);
+});

e2e/coverage-with-projects/package.json

@@ -0,0 +1,13 @@
+{
+  "jest": {
+    "projects": [
+      "<rootDir>/packages/client",
+      "<rootDir>/packages/server"
+    ],
+    "collectCoverageFrom": [
+      "packages/client/**/*.js",
+      "packages/server/**/*.js"
+    ],
+    "testEnvironment": "node"
+  }
+}

e2e/coverage-with-projects/packages/client/client.js

@@ -0,0 +1,16 @@
+/**
+ * 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 add(a, b) {
+  return a + b;
+}
+
+function subtract(a, b) {
+  return a - b;
+}
+
+module.exports = {add, subtract};

e2e/coverage-with-projects/packages/client/client.test.js

@@ -0,0 +1,12 @@
+/**
+ * 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 {add} = require('./client');
+
+test('add function', () => {
+  expect(add(1, 2)).toBe(3);
+});

e2e/coverage-with-projects/packages/client/package.json

@@ -0,0 +1,5 @@
+{
+  "jest": {
+    "testEnvironment": "node"
+  }
+}

e2e/coverage-with-projects/packages/server/package.json

@@ -0,0 +1,5 @@
+{
+  "jest": {
+    "testEnvironment": "node"
+  }
+}

e2e/coverage-with-projects/packages/server/server.js

@@ -0,0 +1,16 @@
+/**
+ * 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 multiply(a, b) {
+  return a * b;
+}
+
+function divide(a, b) {
+  return a / b;
+}
+
+module.exports = {divide, multiply};

e2e/coverage-with-projects/packages/server/server.test.js

@@ -0,0 +1,12 @@
+/**
+ * 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 {multiply} = require('./server');
+
+test('multiply function', () => {
+  expect(multiply(2, 3)).toBe(6);
+});