Implement --watch

api.js

@@ -9,7 +9,7 @@ var figures = require('figures');
 var globby = require('globby');
 var chalk = require('chalk');
 var objectAssign = require('object-assign');
-var commondir = require('commondir');
+var commonPathPrefix = require('common-path-prefix');
 var resolveCwd = require('resolve-cwd');
 var uniqueTempDir = require('unique-temp-dir');
 var findCacheDir = require('find-cache-dir');
@@ -27,6 +27,34 @@ function Api(files, options) {
 
 	this.options = options || {};
 	this.options.require = (this.options.require || []).map(resolveCwd);
+
+	if (!files || files.length === 0) {
+		this.files = [
+			'test.js',
+			'test-*.js',
+			'test'
+		];
+	} else {
+		this.files = files;
+	}
+
+	this.excludePatterns = [
+		'!**/node_modules/**',
+		'!**/fixtures/**',
+		'!**/helpers/**'
+	];
+
+	Object.keys(Api.prototype).forEach(function (key) {
+		this[key] = this[key].bind(this);
+	}, this);
+
+	this._reset();
+}
+
+util.inherits(Api, EventEmitter);
+module.exports = Api;
+
+Api.prototype._reset = function () {
 	this.rejectionCount = 0;
 	this.exceptionCount = 0;
 	this.passCount = 0;
@@ -37,16 +65,9 @@ function Api(files, options) {
 	this.errors = [];
 	this.stats = [];
 	this.tests = [];
-	this.files = files || [];
 	this.base = '';
-
-	Object.keys(Api.prototype).forEach(function (key) {
-		this[key] = this[key].bind(this);
-	}, this);
-}
-
-util.inherits(Api, EventEmitter);
-module.exports = Api;
+	this.explicitTitles = false;
+};
 
 Api.prototype._runFile = function (file) {
 	var options = objectAssign({}, this.options, {
@@ -119,7 +140,7 @@ Api.prototype._handleTest = function (test) {
 };
 
 Api.prototype._prefixTitle = function (file) {
-	if (this.fileCount === 1) {
+	if (this.fileCount === 1 && !this.explicitTitles) {
 		return '';
 	}
 
@@ -141,16 +162,23 @@ Api.prototype._prefixTitle = function (file) {
 	return prefix;
 };
 
-Api.prototype.run = function () {
+Api.prototype.run = function (files) {
 	var self = this;
 
-	return handlePaths(this.files)
+	this._reset();
+	this.explicitTitles = Boolean(files);
+	return handlePaths(files || this.files, this.excludePatterns)
 		.map(function (file) {
 			return path.resolve(file);
 		})
 		.then(function (files) {
 			if (files.length === 0) {
-				return Promise.reject(new AvaError('Couldn\'t find any files to test'));
+				self._handleExceptions({
+					exception: new AvaError('Couldn\'t find any files to test'),
+					file: undefined
+				});
+
+				return [];
 			}
 
 			var cacheEnabled = self.options.cacheEnabled !== false;
@@ -160,7 +188,7 @@ Api.prototype.run = function () {
 			self.options.cacheDir = cacheDir;
 			self.precompiler = new CachingPrecompiler(cacheDir);
 			self.fileCount = files.length;
-			self.base = path.relative('.', commondir('.', files)) + path.sep;
+			self.base = path.relative('.', commonPathPrefix(files)) + path.sep;
 
 			var tests = files.map(self._runFile);
 
@@ -182,7 +210,20 @@ Api.prototype.run = function () {
 							var method = self.options.serial ? 'mapSeries' : 'map';
 
 							resolve(Promise[method](files, function (file, index) {
-								return tests[index].run();
+								return tests[index].run().catch(function (err) {
+									// The test failed catastrophically. Flag it up as an
+									// exception, then return an empty result. Other tests may
+									// continue to run.
+									self._handleExceptions({
+										exception: err,
+										file: file
+									});
+
+									return {
+										stats: {passCount: 0, skipCount: 0, failCount: 0},
+										tests: []
+									};
+								});
 							}));
 						}
 					}
@@ -210,26 +251,14 @@ Api.prototype.run = function () {
 		});
 };
 
-function handlePaths(files) {
-	if (files.length === 0) {
-		files = [
-			'test.js',
-			'test-*.js',
-			'test'
-		];
-	}
-
-	files.push('!**/node_modules/**');
-	files.push('!**/fixtures/**');
-	files.push('!**/helpers/**');
-
+function handlePaths(files, excludePatterns) {
 	// convert pinkie-promise to Bluebird promise
-	files = Promise.resolve(globby(files));
+	files = Promise.resolve(globby(files.concat(excludePatterns)));
 
 	return files
 		.map(function (file) {
 			if (fs.statSync(file).isDirectory()) {
-				return handlePaths([path.join(file, '**', '*.js')]);
+				return handlePaths([path.join(file, '**', '*.js')], excludePatterns);
 			}
 
 			return file;

cli.js

@@ -29,6 +29,7 @@ var verboseReporter = require('./lib/reporters/verbose');
 var miniReporter = require('./lib/reporters/mini');
 var tapReporter = require('./lib/reporters/tap');
 var Logger = require('./lib/logger');
+var watcher = require('./lib/watcher');
 var Api = require('./api');
 
 // Bluebird specific
@@ -48,6 +49,9 @@ var cli = meow([
 	'  --tap, -t        Generate TAP output',
 	'  --verbose, -v    Enable verbose output',
 	'  --no-cache       Disable the transpiler cache',
+	// Leave --watch and --sources undocumented until they're stable enough
+	// '  --watch, -w      Re-run tests when tests and source files change',
+	// '  --source         Pattern to match source files so tests can be re-run (Can be repeated)',
 	'',
 	'Examples',
 	'  ava',
@@ -62,20 +66,23 @@ var cli = meow([
 ], {
 	string: [
 		'_',
-		'require'
+		'require',
+		'source'
 	],
 	boolean: [
 		'fail-fast',
 		'verbose',
 		'serial',
-		'tap'
+		'tap',
+		'watch'
 	],
 	default: conf,
 	alias: {
 		t: 'tap',
 		v: 'verbose',
 		r: 'require',
-		s: 'serial'
+		s: 'serial',
+		w: 'watch'
 	}
 });
 
@@ -112,17 +119,30 @@ api.on('error', logger.unhandledError);
 api.on('stdout', logger.stdout);
 api.on('stderr', logger.stderr);
 
-api.run()
-	.then(function () {
-		logger.finish();
-		logger.exit(api.failCount > 0 || api.rejectionCount > 0 || api.exceptionCount > 0 ? 1 : 0);
-	})
-	.catch(function (err) {
+if (cli.flags.watch) {
+	try {
+		watcher.start(logger, api, arrify(cli.flags.source), process.stdin);
+	} catch (err) {
 		if (err.name === 'AvaError') {
+			// An AvaError may be thrown if chokidar is not installed. Log it nicely.
 			console.log('  ' + colors.error(figures.cross) + ' ' + err.message);
+			logger.exit(1);
 		} else {
-			console.error(colors.stack(err.stack));
+			// Rethrow so it becomes an uncaught exception.
+			throw err;
 		}
-
-		logger.exit(1);
-	});
+	}
+} else {
+	api.run()
+		.then(function () {
+			logger.finish();
+			logger.exit(api.failCount > 0 || api.rejectionCount > 0 || api.exceptionCount > 0 ? 1 : 0);
+		})
+		.catch(function (err) {
+			// Don't swallow exceptions. Note that any expected error should already
+			// have been logged.
+			setImmediate(function () {
+				throw err;
+			});
+		});
+}

lib/logger.js

@@ -25,6 +25,14 @@ Logger.prototype.start = function () {
 	this.write(this.reporter.start());
 };
 
+Logger.prototype.reset = function () {
+	if (!this.reporter.reset) {
+		return;
+	}
+
+	this.write(this.reporter.reset());
+};
+
 Logger.prototype.test = function (test) {
 	this.write(this.reporter.test(test));
 };

lib/reporters/mini.js

@@ -10,14 +10,7 @@ function MiniReporter() {
 		return new MiniReporter();
 	}
 
-	this.passCount = 0;
-	this.failCount = 0;
-	this.skipCount = 0;
-	this.rejectionCount = 0;
-	this.exceptionCount = 0;
-	this.currentStatus = '';
-	this.statusLineCount = 0;
-	this.lastLineTracker = lastLineTracker();
+	this.reset();
 	this.stream = process.stderr;
 	this.stringDecoder = new StringDecoder();
 }
@@ -28,6 +21,17 @@ MiniReporter.prototype.start = function () {
 	return '';
 };
 
+MiniReporter.prototype.reset = function () {
+	this.passCount = 0;
+	this.failCount = 0;
+	this.skipCount = 0;
+	this.rejectionCount = 0;
+	this.exceptionCount = 0;
+	this.currentStatus = '';
+	this.statusLineCount = 0;
+	this.lastLineTracker = lastLineTracker();
+};
+
 MiniReporter.prototype.test = function (test) {
 	var status = '';
 	var title;
@@ -120,11 +124,15 @@ MiniReporter.prototype.finish = function () {
 
 			i++;
 
-			var title = err.type === 'rejection' ? 'Unhandled Rejection' : 'Uncaught Exception';
-			var description = err.stack ? err.stack : JSON.stringify(err);
+			if (err.type === 'exception' && err.name === 'AvaError') {
+				status += '\n\n  ' + colors.error(i + '. ' + err.message) + '\n';
+			} else {
+				var title = err.type === 'rejection' ? 'Unhandled Rejection' : 'Uncaught Exception';
+				var description = err.stack ? err.stack : JSON.stringify(err);
 
-			status += '\n\n  ' + colors.error(i + '.', title) + '\n';
-			status += '  ' + colors.stack(description);
+				status += '\n\n  ' + colors.error(i + '.', title) + '\n';
+				status += '  ' + colors.stack(description);
+			}
 		});
 	}
 

lib/reporters/tap.js

@@ -51,12 +51,17 @@ TapReporter.prototype.test = function (test) {
 TapReporter.prototype.unhandledError = function (err) {
 	var output = [
 		'# ' + err.message,
-		format('not ok %d - %s', ++this.i, err.message),
-		'  ---',
-		'    name: ' + err.name,
-		'    at: ' + getSourceFromStack(err.stack, 1),
-		'  ...'
+		format('not ok %d - %s', ++this.i, err.message)
 	];
+	// AvaErrors don't have stack traces.
+	if (err.type !== 'exception' || err.name !== 'AvaError') {
+		output.push(
+			'  ---',
+			'    name: ' + err.name,
+			'    at: ' + getSourceFromStack(err.stack, 1),
+			'  ...'
+		);
+	}
 
 	return output.join('\n');
 };

lib/reporters/verbose.js

@@ -37,6 +37,10 @@ VerboseReporter.prototype.test = function (test) {
 };
 
 VerboseReporter.prototype.unhandledError = function (err) {
+	if (err.type === 'exception' && err.name === 'AvaError') {
+		return '  ' + colors.error(figures.cross) + ' ' + err.message;
+	}
+
 	var types = {
 		rejection: 'Unhandled Rejection',
 		exception: 'Uncaught Exception'