report unhandled promise rejections

Author: jamestalmage

cli.js

@@ -45,6 +45,7 @@ var cli = meow({
 
 var testCount = 0;
 var fileCount = 0;
+var unhandledRejectionCount = 0;
 var errors = [];
 
 function error(err) {
@@ -116,11 +117,18 @@ function run(file) {
 	return fork(args)
 		.on('stats', stats)
 		.on('test', test)
+		.on('unhandledRejections', rejections)
 		.on('data', function (data) {
 			process.stdout.write(data);
 		});
 }
 
+function rejections(data) {
+	var unhandled = data.unhandledRejections;
+	log.unhandledRejections(data.file, unhandled);
+	unhandledRejectionCount += unhandled.length;
+}
+
 function sum(arr, key) {
 	var result = 0;
 
@@ -145,7 +153,7 @@ function exit(results) {
 	var failed = sum(stats, 'failCount');
 
 	log.write();
-	log.report(passed, failed);
+	log.report(passed, failed, unhandledRejectionCount);
 	log.write();
 
 	if (failed > 0) {
@@ -158,7 +166,7 @@ function exit(results) {
 
 	// timeout required to correctly flush stderr on Node 0.10 Windows
 	setTimeout(function () {
-		process.exit(failed > 0 ? 1 : 0);
+		process.exit(failed > 0 || unhandledRejectionCount > 0 ? 1 : 0);
 	}, 0);
 }
 

lib/babel.js

@@ -1,7 +1,9 @@
 'use strict';
+var loudRejection = require('loud-rejection/api')(process);
 var resolveFrom = require('resolve-from');
 var createEspowerPlugin = require('babel-plugin-espower/create');
 var requireFromString = require('require-from-string');
+var destroyCircular = require('destroy-circular');
 
 var hasGenerators = parseInt(process.version.slice(1), 10) > 0;
 var testPath = process.argv[2];
@@ -45,7 +47,41 @@ if (!avaRequired) {
 }
 
 process.on('message', function (message) {
-	if (message['ava-kill-command']) {
-		process.exit(0);
+	var command = message['ava-child-process-command'];
+	if (command) {
+		process.emit('ava-' + command, message.data);
 	}
 });
+
+process.on('ava-kill', function () {
+	process.exit(0);
+});
+
+process.on('ava-cleanup', function () {
+	var unhandled = loudRejection.currentlyUnhandled();
+	if (unhandled.length) {
+		unhandled = unhandled.map(function (entry) {
+			var err = entry.reason;
+			if (typeof err === 'object') {
+				return destroyCircular(err);
+			}
+			if (typeof err === 'function') {
+				return '[Function ' + err.name + ']';
+			}
+			return err;
+		});
+		process.send({
+			name: 'unhandledRejections',
+			data: {
+				unhandledRejections: unhandled
+			}
+		});
+	}
+
+	setTimeout(function () {
+		process.send({
+			name: 'cleaned-up',
+			data: {}
+		});
+	}, 100);
+});

lib/fork.js

@@ -18,6 +18,10 @@ module.exports = function (args) {
 
 	var ps = childProcess.fork(babel, args, options);
 
+	function send(command, data) {
+		ps.send({'ava-child-process-command': command, 'data': data});
+	}
+
 	var promise = new Promise(function (resolve, reject) {
 		var testResults;
 
@@ -26,7 +30,11 @@ module.exports = function (args) {
 
 			// after all tests are finished and results received
 			// kill the forked process, so AVA can exit safely
-			ps.send({'ava-kill-command': true});
+			send('cleanup', true);
+		});
+
+		ps.on('cleaned-up', function () {
+			send('kill', true);
 		});
 
 		ps.on('error', reject);

lib/logger.js

@@ -70,10 +70,28 @@ x.errors = function (results) {
 	});
 };
 
-x.report = function (passed, failed) {
+x.report = function (passed, failed, unhandled) {
 	if (failed > 0) {
 		log.writelpad(chalk.red(failed, plur('test', failed), 'failed'));
 	} else {
 		log.writelpad(chalk.green(passed, plur('test', passed), 'passed'));
 	}
+	if (unhandled > 0) {
+		log.writelpad(chalk.red(unhandled, 'unhandled', plur('rejection', unhandled)));
+	}
+};
+
+x.unhandledRejections = function (file, rejections) {
+	if (!(rejections && rejections.length)) {
+		return;
+	}
+	rejections.forEach(function (rejection) {
+		log.write(chalk.red('Unhandled Rejection: ', file));
+		if (rejection.stack) {
+			log.writelpad(chalk.red(beautifyStack(rejection.stack)));
+		} else {
+			log.writelpad(chalk.red(JSON.stringify(rejection)));
+		}
+		log.write();
+	});
 };

package.json

@@ -77,6 +77,7 @@
     "globby": "^3.0.1",
     "has-flag": "^1.0.0",
     "is-generator-fn": "^1.0.0",
+    "loud-rejection": "^1.2.0",
     "max-timeout": "^1.0.0",
     "meow": "^3.3.0",
     "plur": "^2.0.0",

test/fixture/loud-rejection.js

@@ -0,0 +1,9 @@
+const test = require('../../');
+
+test('creates an unhandled rejection', t => {
+	Promise.reject(new Error(`You can't handle this!`));
+
+	setTimeout(function () {
+		t.end();
+	});
+});

test/test.js

@@ -1066,6 +1066,15 @@ test('Babel require hook only applies to the test file', function (t) {
 	});
 });
 
+test('Unhandled promises will be reported to console', function (t) {
+	execCli('fixture/loud-rejection.js', function (err, stdout, stderr) {
+		t.ok(err);
+		t.ok(/You can't handle this/.test(stderr));
+		t.ok(/1 unhandled rejection[^s]/.test(stderr));
+		t.end();
+	});
+});
+
 test('absolute paths in CLI', function (t) {
 	t.plan(2);