Add --coverage option to build scripts for tests (#54499)

scripts/build/options.mjs

@@ -4,7 +4,7 @@ import os from "os";
 const ci = ["1", "true"].includes(process.env.CI ?? "");
 
 const parsed = minimist(process.argv.slice(2), {
-    boolean: ["dirty", "light", "colors", "lkg", "soft", "fix", "failed", "keepFailed", "force", "built", "ci", "bundle", "typecheck", "lint"],
+    boolean: ["dirty", "light", "colors", "lkg", "soft", "fix", "failed", "keepFailed", "force", "built", "ci", "bundle", "typecheck", "lint", "coverage"],
     string: ["browser", "tests", "break", "host", "reporter", "stackTraceLimit", "timeout", "shards", "shardId"],
     alias: {
         /* eslint-disable quote-props */
@@ -42,6 +42,7 @@ const parsed = minimist(process.argv.slice(2), {
         bundle: true,
         typecheck: true,
         lint: true,
+        coverage: false,
     }
 });
 
@@ -88,5 +89,6 @@ export default options;
  * @property {boolean} bundle
  * @property {boolean} typecheck
  * @property {boolean} lint
+ * @property {boolean} coverage
  */
 void 0;

scripts/build/tests.mjs

@@ -7,13 +7,14 @@ import path from "path";
 
 import { findUpFile, findUpRoot } from "./findUpDir.mjs";
 import cmdLineOptions from "./options.mjs";
-import { exec } from "./utils.mjs";
+import { exec, ExecError } from "./utils.mjs";
 
 const mochaJs = path.resolve(findUpRoot(), "node_modules", "mocha", "bin", "_mocha");
 export const localBaseline = "tests/baselines/local/";
 export const refBaseline = "tests/baselines/reference/";
 export const localRwcBaseline = "internal/baselines/rwc/local";
 export const refRwcBaseline = "internal/baselines/rwc/reference";
+export const coverageDir = "coverage";
 
 /**
  * @param {string} runJs
@@ -35,11 +36,13 @@ export async function runConsoleTests(runJs, defaultReporter, runInParallel, opt
     const keepFailed = cmdLineOptions.keepFailed;
     const shards = +cmdLineOptions.shards || undefined;
     const shardId = +cmdLineOptions.shardId || undefined;
+    const coverage = cmdLineOptions.coverage;
     if (!cmdLineOptions.dirty) {
         if (options.watching) {
             console.log(chalk.yellowBright(`[watch] cleaning test directories...`));
         }
         await cleanTestDirs();
+        await cleanCoverageDir();
 
         if (options.token?.signaled) {
             return;
@@ -128,21 +131,28 @@ export async function runConsoleTests(runJs, defaultReporter, runInParallel, opt
     /** @type {Error | undefined} */
     let error;
 
+    const savedNodeEnv = process.env.NODE_ENV;
+    const savedNodeV8Coverage = process.env.NODE_V8_COVERAGE;
     try {
-        setNodeEnvToDevelopment();
+        process.env.NODE_ENV = "development";
+        if (coverage) {
+            process.env.NODE_V8_COVERAGE = path.resolve(coverageDir, "tmp");
+        }
 
-        const { exitCode } = await exec(process.execPath, args, { token: options.token });
-        if (exitCode !== 0) {
-            errorStatus = exitCode;
-            error = new Error(`Process exited with status code ${errorStatus}.`);
+        await exec(process.execPath, args, { token: options.token });
+        if (coverage) {
+            await exec("npm", ["--prefer-offline", "exec", "--", "c8", "report"], { token: options.token });
         }
     }
     catch (e) {
-        errorStatus = undefined;
+        errorStatus = e instanceof ExecError ? e.exitCode ?? undefined : undefined;
         error = /** @type {Error} */ (e);
     }
     finally {
-        restoreSavedNodeEnv();
+        if (coverage) {
+            process.env.NODE_V8_COVERAGE = savedNodeV8Coverage;
+        }
+        process.env.NODE_ENV = savedNodeEnv;
     }
 
     await del("test.config");
@@ -169,6 +179,10 @@ export async function cleanTestDirs() {
     await fs.promises.mkdir(localBaseline, { recursive: true });
 }
 
+async function cleanCoverageDir() {
+    await del([coverageDir]);
+}
+
 /**
  * used to pass data from command line directly to run.js
  * @param {string} tests
@@ -200,17 +214,6 @@ export function writeTestConfigFile(tests, runners, light, taskConfigsFolder, wo
     fs.writeFileSync("test.config", testConfigContents);
 }
 
-/** @type {string | undefined} */
-let savedNodeEnv;
-function setNodeEnvToDevelopment() {
-    savedNodeEnv = process.env.NODE_ENV;
-    process.env.NODE_ENV = "development";
-}
-
-function restoreSavedNodeEnv() {
-    process.env.NODE_ENV = savedNodeEnv;
-}
-
 function deleteTemporaryProjectOutput() {
     return del(path.join(localBaseline, "projectOutput/"));
 }

scripts/build/utils.mjs

@@ -35,7 +35,7 @@ export async function exec(cmd, args, options = {}) {
                 }
                 else {
                     const reason = options.token?.signaled ? options.token.reason ?? new CancelError() :
-                        new Error(`Process exited with code: ${exitCode}`);
+                        new ExecError(exitCode);
                     reject(reason);
                 }
                 subscription?.unsubscribe();
@@ -53,6 +53,19 @@ export async function exec(cmd, args, options = {}) {
     }));
 }
 
+export class ExecError extends Error {
+    exitCode;
+
+    /**
+     * @param {number | null} exitCode
+     * @param {string} message
+     */
+    constructor(exitCode, message = `Process exited with code: ${exitCode}`) {
+        super(message);
+        this.exitCode = exitCode;
+    }
+}
+
 /**
  * Reads JSON data with optional comments using the LKG TypeScript compiler
  * @param {string} jsonPath