Interrupt test workers when a test fails and --fail-fast is enabled

If a failure occurs in one worker, attempt to interrupt
other workers. This only works as long as the other worker has not yet
started running concurrent tests.

Fixes #1158.

Author: novemberborn

api.js

@@ -99,6 +99,10 @@ class Api extends EventEmitter {
 						if (test.error) {
 							bailed = true;
 						}
+
+						for (const fork of pendingForks) {
+							fork.notifyOfPeerFailure();
+						}
 					});
 				}
 

lib/fork.js

@@ -142,15 +142,14 @@ module.exports = (file, opts, execArgv) => {
 		return promise;
 	};
 
-	promise.send = (name, data) => {
-		send(name, data);
-		return promise;
-	};
-
 	promise.exit = () => {
 		send('init-exit');
 		return promise;
 	};
 
+	promise.notifyOfPeerFailure = () => {
+		send('peer-failed');
+	};
+
 	return promise;
 };

lib/runner.js

@@ -24,6 +24,7 @@ class Runner extends EventEmitter {
 
 		this.activeRunnables = new Set();
 		this.boundCompareTestSnapshot = this.compareTestSnapshot.bind(this);
+		this.interrupted = false;
 		this.snapshots = null;
 		this.stats = {
 			failCount: 0,
@@ -402,8 +403,8 @@ class Runner extends EventEmitter {
 			return serialTests.reduce((prev, task) => {
 				return prev.then(prevOk => {
 					// Prevent subsequent tests from running if `failFast` is enabled and
-					// the previous test failed.
-					if (!prevOk && this.failFast) {
+					// the previous test failed, or an interrupt was received.
+					if ((!prevOk && this.failFast) || this.interrupted) {
 						return false;
 					}
 
@@ -415,8 +416,8 @@ class Runner extends EventEmitter {
 			const beforeHooksOk = prevOkays[0];
 			const serialOk = prevOkays[1];
 			// Don't run tests if a `before` hook failed, or if `failFast` is enabled
-			// and a previous serial test failed.
-			if (!beforeHooksOk || (!serialOk && this.failFast)) {
+			// and a previous serial test failed, or an interrupt was received.
+			if (!beforeHooksOk || (!serialOk && this.failFast) || this.interrupted) {
 				return false;
 			}
 
@@ -448,6 +449,10 @@ class Runner extends EventEmitter {
 			todoTitles
 		});
 	}
+
+	interrupt() {
+		this.interrupted = true;
+	}
 }
 
 module.exports = Runner;

lib/test-worker.js

@@ -217,6 +217,12 @@ process.on('ava-init-exit', () => {
 	exit();
 });
 
+process.on('ava-peer-failed', () => {
+	if (runner) {
+		runner.interrupt();
+	}
+});
+
 // Store value in case to prevent required modules from modifying it.
 const testPath = opts.file;
 

test/api.js

@@ -202,7 +202,7 @@ test('display filename prefixes for failed test stack traces in subdirs', t => {
 		});
 });
 
-test('fail-fast mode - single file', t => {
+test('fail-fast mode - single file & serial', t => {
 	const api = apiCreator({
 		failFast: true
 	});
@@ -236,7 +236,7 @@ test('fail-fast mode - single file', t => {
 		});
 });
 
-test('fail-fast mode - multiple files', t => {
+test('fail-fast mode - multiple files & serial', t => {
 	const api = apiCreator({
 		failFast: true,
 		serial: true
@@ -271,7 +271,48 @@ test('fail-fast mode - multiple files', t => {
 		});
 });
 
-test('fail-fast mode - crash', t => {
+test('fail-fast mode - multiple files & interrupt', t => {
+	const api = apiCreator({
+		failFast: true,
+		concurrency: 2
+	});
+
+	const tests = [];
+
+	api.on('test-run', runStatus => {
+		runStatus.on('test', test => {
+			tests.push({
+				ok: !test.error,
+				title: test.title
+			});
+		});
+	});
+
+	return api.run([
+		path.join(__dirname, 'fixture/fail-fast/multiple-files/fails.js'),
+		path.join(__dirname, 'fixture/fail-fast/multiple-files/passes-slow.js')
+	])
+		.then(result => {
+			t.ok(api.options.failFast);
+			t.strictDeepEqual(tests, [{
+				ok: true,
+				title: `fails ${figures.pointerSmall} first pass`
+			}, {
+				ok: false,
+				title: `fails ${figures.pointerSmall} second fail`
+			}, {
+				ok: true,
+				title: `fails ${figures.pointerSmall} third pass`
+			}, {
+				ok: true,
+				title: `passes-slow ${figures.pointerSmall} first pass`
+			}]);
+			t.is(result.passCount, 3);
+			t.is(result.failCount, 1);
+		});
+});
+
+test('fail-fast mode - crash & serial', t => {
 	const api = apiCreator({
 		failFast: true,
 		serial: true
@@ -307,7 +348,7 @@ test('fail-fast mode - crash', t => {
 		});
 });
 
-test('fail-fast mode - timeout', t => {
+test('fail-fast mode - timeout & serial', t => {
 	const api = apiCreator({
 		failFast: true,
 		serial: true,

test/fixture/fail-fast/multiple-files/passes-slow.js

@@ -0,0 +1,10 @@
+import test from '../../../../';
+
+test.serial('first pass', async t => {
+	t.pass();
+	return new Promise(resolve => setTimeout(resolve, 3000));
+});
+
+test('second pass', t => {
+	t.pass();
+});