feat: parallel test running for node and the browser

Author: brandonocasey

package.json

@@ -32,6 +32,7 @@
   "files": [
     "bin/",
     "src/cli/",
+    "src/workers/",
     "qunit/qunit.js",
     "qunit/qunit.css",
     "LICENSE.txt"

src/cli/run.js

@@ -10,6 +10,7 @@ const { findReporter } = require( "./find-reporter" );
 
 const DEBOUNCE_WATCH_LENGTH = 60;
 const DEBOUNCE_RESTART_LENGTH = 200 - DEBOUNCE_WATCH_LENGTH;
+const os = require( "os" );
 
 const changedPendingPurge = [];
 
@@ -20,15 +21,27 @@ async function run( args, options ) {
 	// Default to non-zero exit code to avoid false positives
 	process.exitCode = 1;
 
-	const files = utils.getFilesFromArgs( args );
-
 	QUnit = requireQUnit();
 
+	let globalConfig = {};
+
+	// TODO: Enable mode where QUnit is not auto-injected, but other setup is
+	// still done automatically.
+	if ( global.QUnit && global.QUnit.config ) {
+		globalConfig = global.QUnit.config;
+	}
+	global.QUnit = QUnit;
+
+	Object.keys( globalConfig ).forEach( function( key ) {
+		QUnit.config[ key ] = globalConfig[ key ];
+	} );
+
 	if ( options.filter ) {
 		QUnit.config.filter = options.filter;
 	}
 
 	const seed = options.seed;
+
 	if ( seed ) {
 		if ( seed === true ) {
 			QUnit.config.seed = Math.random().toString( 36 ).slice( 2 );
@@ -39,65 +52,80 @@ async function run( args, options ) {
 		console.log( `Running tests with seed: ${QUnit.config.seed}` );
 	}
 
-	// TODO: Enable mode where QUnit is not auto-injected, but other setup is
-	// still done automatically.
-	global.QUnit = QUnit;
+	if ( !options.noReporter ) {
+		findReporter( options.reporter, QUnit.reporters ).init( QUnit );
+	}
 
-	options.requires.forEach( requireFromCWD );
+	if ( !QUnit.config.isWorker ) {
+		QUnit.config.maxThreads = os.cpus().length;
+		QUnit.config.workerType = "NodeWorker";
+		QUnit.config.files = args;
+
+		// eslint-disable-next-line node/no-unsupported-features/es-syntax
+		const nodeWorkerModule = await import( "../workers/node-worker.mjs" );
+		const NodeWorker = nodeWorkerModule.default;
+
+		QUnit.WorkerFactory.registerWorkerClass( NodeWorker );
+
+	} else {
+		options.requires.forEach( requireFromCWD );
+
+		const files = utils.getFilesFromArgs( args );
+
+		for ( let i = 0; i < files.length; i++ ) {
+			const filePath = path.resolve( process.cwd(), files[ i ] );
+			delete require.cache[ filePath ];
+
+			// Node.js 12.0.0 has node_module_version=72
+			// https://nodejs.org/en/download/releases/
+			const nodeVint = process.config.variables.node_module_version;
 
-	findReporter( options.reporter, QUnit.reporters ).init( QUnit );
-
-	for ( let i = 0; i < files.length; i++ ) {
-		const filePath = path.resolve( process.cwd(), files[ i ] );
-		delete require.cache[ filePath ];
-
-		// Node.js 12.0.0 has node_module_version=72
-		// https://nodejs.org/en/download/releases/
-		const nodeVint = process.config.variables.node_module_version;
-
-		try {
-
-			// QUnit supports passing ESM files to the 'qunit' command when used on
-			// Node.js 12 or later. The dynamic import() keyword supports both CommonJS files
-			// (.js, .cjs) and ESM files (.mjs), so we could simply use that unconditionally on
-			// newer Node versions, regardless of the given file path.
-			//
-			// But:
-			// - Node.js 12 emits a confusing "ExperimentalWarning" when using import(),
-			//   even if just to load a non-ESM file. So we should try to avoid it on non-ESM.
-			// - This Node.js feature is still considered experimental so to avoid unexpected
-			//   breakage we should continue using require(). Consider flipping once stable and/or
-			//   as part of QUnit 3.0.
-			// - Plugins and CLI bootstrap scripts may be hooking into require.extensions to modify
-			//   or transform code as it gets loaded. For compatibility with that, we should
-			//   support that until at least QUnit 3.0.
-			// - File extensions are not sufficient to differentiate between CJS and ESM.
-			//   Use of ".mjs" is optional, as a package may configure Node to default to ESM
-			//   and optionally use ".cjs" for CJS files.
-			//
-			// https://nodejs.org/docs/v12.7.0/api/modules.html#modules_addenda_the_mjs_extension
-			// https://nodejs.org/docs/v12.7.0/api/esm.html#esm_code_import_code_expressions
-			// https://github.com/qunitjs/qunit/issues/1465
 			try {
-				require( filePath );
-			} catch ( e ) {
-				if ( ( e.code === "ERR_REQUIRE_ESM" ||
-					( e instanceof SyntaxError &&
-						e.message === "Cannot use import statement outside a module" ) ) &&
-					( !nodeVint || nodeVint >= 72 ) ) {
-
-					// filePath is an absolute file path here (per path.resolve above).
-					// On Windows, Node.js enforces that absolute paths via ESM use valid URLs,
-					// e.g. file-protocol) https://github.com/qunitjs/qunit/issues/1667
-					await import( url.pathToFileURL( filePath ) ); // eslint-disable-line node/no-unsupported-features/es-syntax
-				} else {
-					throw e;
+
+				// QUnit supports passing ESM files to the 'qunit' command when used on
+				// Node.js 12 or later. The dynamic import() keyword supports both CommonJS files
+				// (.js, .cjs) and ESM files (.mjs), so we could simply use that unconditionally on
+				// newer Node versions, regardless of the given file path.
+				//
+				// But:
+				// - Node.js 12 emits a confusing "ExperimentalWarning" when using import(),
+				//   even if just to load a non-ESM file. So we should try to avoid it on non-ESM.
+				// - This Node.js feature is still considered experimental so to avoid unexpected
+				//   breakage we should continue using require(). Consider flipping once stable and/or
+				//   as part of QUnit 3.0.
+				// - Plugins and CLI bootstrap scripts may be hooking into require.extensions to modify
+				//   or transform code as it gets loaded. For compatibility with that, we should
+				//   support that until at least QUnit 3.0.
+				// - File extensions are not sufficient to differentiate between CJS and ESM.
+				//   Use of ".mjs" is optional, as a package may configure Node to default to ESM
+				//   and optionally use ".cjs" for CJS files.
+				//
+				// https://nodejs.org/docs/v12.7.0/api/modules.html#modules_addenda_the_mjs_extension
+				// https://nodejs.org/docs/v12.7.0/api/esm.html#esm_code_import_code_expressions
+				// https://github.com/qunitjs/qunit/issues/1465
+				try {
+					require( filePath );
+				} catch ( e ) {
+					if ( ( e.code === "ERR_REQUIRE_ESM" ||
+						( e instanceof SyntaxError &&
+							e.message === "Cannot use import statement outside a module" ) ) &&
+						( !nodeVint || nodeVint >= 72 ) ) {
+
+						// filePath is an absolute file path here (per path.resolve above).
+						// On Windows, Node.js enforces that absolute paths via ESM use valid URLs,
+						// e.g. file-protocol) https://github.com/qunitjs/qunit/issues/1667
+						await import( url.pathToFileURL( filePath ) ); // eslint-disable-line node/no-unsupported-features/es-syntax
+					} else {
+						throw e;
+					}
 				}
+			} catch ( e ) {
+				const error = new Error(
+					`Failed to load file ${files[ i ]}\n${e.name}: ${e.message}`
+				);
+				error.stack = e.stack;
+				QUnit.onUncaughtException( error );
 			}
-		} catch ( e ) {
-			const error = new Error( `Failed to load file ${files[ i ]}\n${e.name}: ${e.message}` );
-			error.stack = e.stack;
-			QUnit.onUncaughtException( error );
 		}
 	}
 
@@ -141,7 +169,9 @@ async function run( args, options ) {
 		}
 	} );
 
-	QUnit.start();
+	if ( !QUnit.config.isWorker ) {
+		QUnit.start();
+	}
 }
 
 run.restart = function( args ) {