Clean up collecting and running tests

Test runners will now run tests as soon as (in the next tick) they're
declared. The main process no longer instructs the workers to start
running tests.

Various IPC commands had to be changed to ensure we can still detect
whether "ava" is loaded, or whether a test file contains no actual
tests.

Fixes #1674.

Author: novemberborn

api.js

@@ -157,7 +157,10 @@ class Api extends EventEmitter {
 							let forked;
 							return Bluebird.resolve(
 								this._computeForkExecArgv().then(execArgv => {
-									const options = Object.assign({}, apiOptions);
+									const options = Object.assign({}, apiOptions, {
+										// If we're looking for matches, run every single test process in exclusive-only mode
+										runOnlyExclusive: apiOptions.match.length > 0 || runtimeOptions.runOnlyExclusive === true
+									});
 									if (precompilation) {
 										options.cacheDir = precompilation.cacheDir;
 										options.precompiled = precompilation.map;
@@ -173,12 +176,6 @@ class Api extends EventEmitter {
 									pendingForks.add(forked);
 									runStatus.observeFork(forked);
 									restartTimer();
-
-									forked.run({
-										// If we're looking for matches, run every single test process in exclusive-only mode
-										runOnlyExclusive: apiOptions.match.length > 0 || runtimeOptions.runOnlyExclusive === true
-									});
-
 									return forked;
 								}).catch(err => {
 									// Prevent new test files from running.

lib/fork.js

@@ -59,6 +59,7 @@ module.exports = (file, opts, execArgv) => {
 		}
 	};
 
+	let loadedFile = false;
 	const testResults = [];
 	let results;
 
@@ -100,21 +101,20 @@ module.exports = (file, opts, execArgv) => {
 
 			if (results) {
 				resolve(results);
+			} else if (loadedFile) {
+				reject(new AvaError(`No tests found in ${relFile}`));
 			} else {
 				reject(new AvaError(`Test results were not received from ${relFile}`));
 			}
 		});
 
-		ps.on('no-tests', data => {
-			send('teardown');
-
-			let message = `No tests found in ${relFile}`;
+		ps.on('loaded-file', data => {
+			loadedFile = true;
 
 			if (!data.avaRequired) {
-				message += ', make sure to import "ava" at the top of your test file';
+				send('teardown');
+				reject(new AvaError(`No tests found in ${relFile}, make sure to import "ava" at the top of your test file`));
 			}
-
-			reject(new AvaError(message));
 		});
 	});
 
@@ -152,25 +152,5 @@ module.exports = (file, opts, execArgv) => {
 		return promise;
 	};
 
-	// Send 'run' event only when fork is listening for it
-	let isReady = false;
-
-	ps.on('stats', () => {
-		isReady = true;
-	});
-
-	promise.run = options => {
-		if (isReady) {
-			send('run', options);
-			return promise;
-		}
-
-		ps.on('stats', () => {
-			send('run', options);
-		});
-
-		return promise;
-	};
-
 	return promise;
 };

lib/main.js

@@ -11,7 +11,8 @@ const runner = new Runner({
 	projectDir: opts.projectDir,
 	serial: opts.serial,
 	updateSnapshots: opts.updateSnapshots,
-	snapshotDir: opts.snapshotDir
+	snapshotDir: opts.snapshotDir,
+	runOnlyExclusive: opts.runOnlyExclusive
 });
 
 worker.setRunner(runner);

lib/runner.js

@@ -127,6 +127,7 @@ class Runner extends EventEmitter {
 		this.serial = options.serial;
 		this.updateSnapshots = options.updateSnapshots;
 		this.snapshotDir = options.snapshotDir;
+		this.runOnlyExclusive = options.runOnlyExclusive;
 
 		this.hasStarted = false;
 		this.results = [];
@@ -208,6 +209,13 @@ class Runner extends EventEmitter {
 			fn,
 			title
 		});
+
+		if (!this.scheduledStart) {
+			this.scheduledStart = true;
+			process.nextTick(() => {
+				this.emit('start', this._run());
+			});
+		}
 	}
 
 	addTestResult(result) {
@@ -294,12 +302,13 @@ class Runner extends EventEmitter {
 		}
 	}
 
-	run(options) {
-		if (options.runOnlyExclusive && !this.tests.hasExclusive) {
+	_run() {
+		this.hasStarted = true;
+
+		if (this.runOnlyExclusive && !this.tests.hasExclusive) {
 			return Promise.resolve(null);
 		}
 
-		this.hasStarted = true;
 		this.tests.on('test', result => {
 			this.addTestResult(result);
 		});

lib/test-worker.js

@@ -19,7 +19,6 @@
 const currentlyUnhandled = require('currently-unhandled')();
 const isObj = require('is-obj');
 
-const nowAndTimers = require('./now-and-timers');
 const adapter = require('./process-adapter');
 const serializeError = require('./serialize-error');
 const opts = require('./worker-options').get();
@@ -58,11 +57,20 @@ exports.setRunner = newRunner => {
 			touchedFiles.add(file);
 		}
 	});
-	runner.on('test', props => {
-		if (exiting) {
-			return;
-		}
+	runner.on('start', promise => {
+		adapter.send('stats', {
+			testCount: runner.tests.testCount,
+			hasExclusive: runner.tests.hasExclusive
+		});
 
+		promise.then(() => {
+			runner.saveSnapshotState();
+			return exit();
+		}).catch(err => {
+			handleUncaughtException(err);
+		});
+	});
+	runner.on('test', props => {
 		const hasError = typeof props.error !== 'undefined';
 		// Don't send anything if it's a passed hook
 		if (!hasError && props.type !== 'test') {
@@ -190,44 +198,14 @@ try {
 } catch (err) {
 	handleUncaughtException(err);
 } finally {
-	if (runner) {
-		nowAndTimers.setImmediate(() => {
-			const hasExclusive = runner.tests.hasExclusive;
-			const numberOfTests = runner.tests.testCount;
-
-			if (numberOfTests === 0) {
-				adapter.send('no-tests', {avaRequired: true});
-				return;
-			}
+	adapter.send('loaded-file', {avaRequired: Boolean(runner)});
 
-			adapter.send('stats', {
-				testCount: numberOfTests,
-				hasExclusive
-			});
-
-			process.on('ava-run', options => {
-				// Unreference the IPC channel. This stops it from keeping the event loop
-				// busy, which means the `beforeExit` event can be used to detect when tests
-				// stall.
-				adapter.ipcChannel.unref();
-
-				runner.run(options)
-					.then(() => {
-						runner.saveSnapshotState();
-
-						return exit();
-					})
-					.catch(err => {
-						handleUncaughtException(err);
-					});
-			});
-
-			process.on('ava-init-exit', () => {
-				exit();
-			});
-		});
-	} else {
-		// If AVA was not required, show an error
-		adapter.send('no-tests', {avaRequired: false});
+	if (runner) {
+		// Unreference the IPC channel if the test file required AVA. This stops it
+		// from keeping the event loop busy, which means the `beforeExit` event can be
+		// used to detect when tests stall.
+		// If AVA was not required then the parent process will initiated a teardown
+		// sequence, for which this process ought to stay active.
+		adapter.ipcChannel.unref();
 	}
 }

profile.js

@@ -97,6 +97,8 @@ babelConfigHelper.build(process.cwd(), cacheDir, babelConfigHelper.validate(conf
 		};
 
 		const events = new EventEmitter();
+		events.on('loaded-file', () => {});
+
 		let uncaughtExceptionCount = 0;
 
 		// Mock the behavior of a parent process

test/fork.js

@@ -35,7 +35,6 @@ test('emits test event', t => {
 	t.plan(1);
 
 	fork(fixture('generators.js'))
-		.run({})
 		.on('test', tt => {
 			t.is(tt.title, 'generator function');
 			t.end();
@@ -48,7 +47,6 @@ test('resolves promise with tests info', t => {
 	const file = fixture('generators.js');
 
 	return fork(file)
-		.run({})
 		.then(info => {
 			t.is(info.stats.passCount, 1);
 			t.is(info.tests.length, 1);
@@ -64,7 +62,6 @@ test('exit after tests are finished', t => {
 	let cleanupCompleted = false;
 
 	fork(fixture('slow-exit.js'))
-		.run({})
 		.on('exit', () => {
 			t.true(Date.now() - start < 10000, 'test waited for a pending setTimeout');
 			t.true(cleanupCompleted, 'cleanup did not complete');
@@ -104,7 +101,6 @@ test('rejects promise if the process is killed', t => {
 
 test('fake timers do not break duration', t => {
 	return fork(fixture('fake-timers.js'))
-		.run({})
 		.then(info => {
 			const duration = info.tests[0].duration;
 			t.true(duration < 1000, `${duration} < 1000`);
@@ -128,7 +124,6 @@ test('destructuring of `t` is allowed', t => {
 
 test('babelrc is ignored', t => {
 	return fork(fixture('babelrc/test.js'))
-		.run({})
 		.then(info => {
 			t.is(info.stats.passCount, 1);
 			t.end();
@@ -139,7 +134,6 @@ test('@std/esm support', t => {
 	return fork(fixture('std-esm/test.js'), {
 		require: [require.resolve('@std/esm')]
 	})
-		.run({})
 		.then(info => {
 			t.is(info.stats.passCount, 1);
 			t.end();
@@ -151,9 +145,9 @@ test('color support is initialized correctly', t => {
 	t.plan(1);
 
 	return Promise.all([
-		fork(fixture('chalk-enabled.js'), {color: true}).run({}),
-		fork(fixture('chalk-disabled.js'), {color: false}).run({}),
-		fork(fixture('chalk-disabled.js'), {}).run({})
+		fork(fixture('chalk-enabled.js'), {color: true}),
+		fork(fixture('chalk-disabled.js'), {color: false}),
+		fork(fixture('chalk-disabled.js'), {})
 	]).then(infos => {
 		for (const info of infos) {
 			if (info.stats.failCount > 0) {