diff --git a/lib/browser/growl.js b/lib/browser/growl.js
index a67648979c..d04f124c0e 100644
--- a/lib/browser/growl.js
+++ b/lib/browser/growl.js
@@ -10,6 +10,7 @@
  */
 var Date = global.Date;
 var setTimeout = global.setTimeout;
+var Runner = require('../runner');
 
 /**
  * Checks if browser notification support exists.
@@ -53,7 +54,7 @@ exports.notify = function(runner) {
       .catch(notPermitted);
   };
 
-  runner.once('end', sendNotification);
+  runner.once(Runner.constants.RUNNER_EVENT_END, sendNotification);
 };
 
 /**
diff --git a/lib/growl.js b/lib/growl.js
index eae2281823..ba0e57f513 100644
--- a/lib/growl.js
+++ b/lib/growl.js
@@ -8,6 +8,7 @@
 const os = require('os');
 const path = require('path');
 const {sync: which} = require('which');
+const Runner = require('./runner');
 
 /**
  * @summary
@@ -41,7 +42,7 @@ exports.isCapable = () => {
  * @param {Runner} runner - Runner instance.
  */
 exports.notify = runner => {
-  runner.once('end', () => {
+  runner.once(Runner.constants.RUNNER_EVENT_END, () => {
     display(runner);
   });
 };
diff --git a/lib/interfaces/bdd.js b/lib/interfaces/bdd.js
index 87408f8a8d..f091c20c91 100644
--- a/lib/interfaces/bdd.js
+++ b/lib/interfaces/bdd.js
@@ -1,6 +1,7 @@
 'use strict';
 
 var Test = require('../test');
+var Suite = require('../suite');
 
 /**
  * BDD-style interface:
@@ -22,7 +23,11 @@ var Test = require('../test');
 module.exports = function bddInterface(suite) {
   var suites = [suite];
 
-  suite.on('pre-require', function(context, file, mocha) {
+  suite.on(Suite.constants.SUITE_EVENT_PRE_REQUIRE, function(
+    context,
+    file,
+    mocha
+  ) {
     var common = require('./common')(suites, context, mocha);
 
     context.before = common.before;
diff --git a/lib/interfaces/exports.js b/lib/interfaces/exports.js
index da5e5d84d8..23fa813bd9 100644
--- a/lib/interfaces/exports.js
+++ b/lib/interfaces/exports.js
@@ -22,7 +22,7 @@ var Test = require('../test');
 module.exports = function(suite) {
   var suites = [suite];
 
-  suite.on('require', visit);
+  suite.on(Suite.constants.SUITE_EVENT_REQUIRE, visit);
 
   function visit(obj, file) {
     var suite;
diff --git a/lib/interfaces/qunit.js b/lib/interfaces/qunit.js
index becc110859..25e307cd42 100644
--- a/lib/interfaces/qunit.js
+++ b/lib/interfaces/qunit.js
@@ -1,6 +1,7 @@
 'use strict';
 
 var Test = require('../test');
+var Suite = require('../suite');
 
 /**
  * QUnit-style interface:
@@ -30,7 +31,11 @@ var Test = require('../test');
 module.exports = function qUnitInterface(suite) {
   var suites = [suite];
 
-  suite.on('pre-require', function(context, file, mocha) {
+  suite.on(Suite.constants.SUITE_EVENT_PRE_REQUIRE, function(
+    context,
+    file,
+    mocha
+  ) {
     var common = require('./common')(suites, context, mocha);
 
     context.before = common.before;
diff --git a/lib/interfaces/tdd.js b/lib/interfaces/tdd.js
index c36c7afc44..a4d7578de5 100644
--- a/lib/interfaces/tdd.js
+++ b/lib/interfaces/tdd.js
@@ -1,6 +1,7 @@
 'use strict';
 
 var Test = require('../test');
+var Suite = require('../suite');
 
 /**
  * TDD-style interface:
@@ -30,7 +31,11 @@ var Test = require('../test');
 module.exports = function(suite) {
   var suites = [suite];
 
-  suite.on('pre-require', function(context, file, mocha) {
+  suite.on(Suite.constants.SUITE_EVENT_PRE_REQUIRE, function(
+    context,
+    file,
+    mocha
+  ) {
     var common = require('./common')(suites, context, mocha);
 
     context.setup = common.beforeEach;
diff --git a/lib/mocha.js b/lib/mocha.js
index c703e09dee..9cec5ef5b3 100644
--- a/lib/mocha.js
+++ b/lib/mocha.js
@@ -14,6 +14,8 @@ var utils = require('./utils');
 var mocharc = require('./mocharc.json');
 var assign = require('object.assign').getPolyfill();
 var errors = require('./errors');
+var Suite = require('./suite');
+var createStatsCollector = require('./stats-collector');
 var createInvalidReporterError = errors.createInvalidReporterError;
 var createInvalidInterfaceError = errors.createInvalidInterfaceError;
 
@@ -51,7 +53,7 @@ exports.Context = require('./context');
  * @memberof Mocha
  */
 exports.Runner = require('./runner');
-exports.Suite = require('./suite');
+exports.Suite = Suite;
 exports.Hook = require('./hook');
 exports.Test = require('./test');
 
@@ -276,7 +278,7 @@ Mocha.prototype.ui = function(name) {
   }
   this._ui = this._ui(this.suite);
 
-  this.suite.on('pre-require', function(context) {
+  this.suite.on(Suite.constants.SUITE_EVENT_PRE_REQUIRE, function(context) {
     exports.afterEach = context.afterEach || context.teardown;
     exports.after = context.after || context.suiteTeardown;
     exports.beforeEach = context.beforeEach || context.setup;
@@ -313,9 +315,9 @@ Mocha.prototype.loadFiles = function(fn) {
   var suite = this.suite;
   this.files.forEach(function(file) {
     file = path.resolve(file);
-    suite.emit('pre-require', global, file, self);
-    suite.emit('require', require(file), file, self);
-    suite.emit('post-require', global, file, self);
+    suite.emit(Suite.constants.SUITE_EVENT_PRE_REQUIRE, global, file, self);
+    suite.emit(Suite.constants.SUITE_EVENT_REQUIRE, require(file), file, self);
+    suite.emit(Suite.constants.SUITE_EVENT_POST_REQUIRE, global, file, self);
   });
   fn && fn();
 };
@@ -759,6 +761,7 @@ Mocha.prototype.run = function(fn) {
   var options = this.options;
   options.files = this.files;
   var runner = new exports.Runner(suite, options.delay);
+  createStatsCollector(runner);
   var reporter = new this._reporter(runner, options);
   runner.ignoreLeaks = options.ignoreLeaks !== false;
   runner.fullStackTrace = options.fullStackTrace;
diff --git a/lib/reporters/base.js b/lib/reporters/base.js
index 16d4ca586e..5782ed95b4 100644
--- a/lib/reporters/base.js
+++ b/lib/reporters/base.js
@@ -11,6 +11,7 @@ var diff = require('diff');
 var milliseconds = require('ms');
 var utils = require('../utils');
 var supportsColor = process.browser ? null : require('supports-color');
+var Runner = require('../runner');
 
 /**
  * Expose `Base`.
@@ -274,7 +275,7 @@ function Base(runner) {
   this.stats = runner.stats; // assigned so Reporters keep a closer reference
   this.runner = runner;
 
-  runner.on('pass', function(test) {
+  runner.on(Runner.constants.RUNNER_EVENT_PASS, function(test) {
     if (test.duration > test.slow()) {
       test.speed = 'slow';
     } else if (test.duration > test.slow() / 2) {
@@ -284,7 +285,7 @@ function Base(runner) {
     }
   });
 
-  runner.on('fail', function(test, err) {
+  runner.on(Runner.constants.RUNNER_EVENT_FAIL, function(test, err) {
     if (showDiff(err)) {
       stringifyDiffObjs(err);
     }
diff --git a/lib/reporters/doc.js b/lib/reporters/doc.js
index ce183d6766..97f3e13b7a 100644
--- a/lib/reporters/doc.js
+++ b/lib/reporters/doc.js
@@ -8,6 +8,7 @@
 
 var Base = require('./base');
 var utils = require('../utils');
+var Runner = require('../runner');
 
 /**
  * Expose `Doc`.
@@ -33,7 +34,7 @@ function Doc(runner) {
     return Array(indents).join('  ');
   }
 
-  runner.on('suite', function(suite) {
+  runner.on(Runner.constants.RUNNER_EVENT_SUITE, function(suite) {
     if (suite.root) {
       return;
     }
@@ -54,13 +55,13 @@ function Doc(runner) {
     --indents;
   });
 
-  runner.on('pass', function(test) {
+  runner.on(Runner.constants.RUNNER_EVENT_PASS, function(test) {
     console.log('%s  <dt>%s</dt>', indent(), utils.escape(test.title));
     var code = utils.escape(utils.clean(test.body));
     console.log('%s  <dd><pre><code>%s</code></pre></dd>', indent(), code);
   });
 
-  runner.on('fail', function(test, err) {
+  runner.on(Runner.constants.RUNNER_EVENT_FAIL, function(test, err) {
     console.log(
       '%s  <dt class="error">%s</dt>',
       indent(),
diff --git a/lib/reporters/dot.js b/lib/reporters/dot.js
index 8479c31e6d..3fb9bc27c8 100644
--- a/lib/reporters/dot.js
+++ b/lib/reporters/dot.js
@@ -8,6 +8,7 @@
 
 var Base = require('./base');
 var inherits = require('../utils').inherits;
+var Runner = require('../runner');
 
 /**
  * Expose `Dot`.
@@ -31,18 +32,18 @@ function Dot(runner) {
   var width = (Base.window.width * 0.75) | 0;
   var n = -1;
 
-  runner.on('start', function() {
+  runner.on(Runner.constants.RUNNER_EVENT_START, function() {
     process.stdout.write('\n');
   });
 
-  runner.on('pending', function() {
+  runner.on(Runner.constants.RUNNER_EVENT_PENDING, function() {
     if (++n % width === 0) {
       process.stdout.write('\n  ');
     }
     process.stdout.write(Base.color('pending', Base.symbols.comma));
   });
 
-  runner.on('pass', function(test) {
+  runner.on(Runner.constants.RUNNER_EVENT_PASS, function(test) {
     if (++n % width === 0) {
       process.stdout.write('\n  ');
     }
@@ -53,14 +54,14 @@ function Dot(runner) {
     }
   });
 
-  runner.on('fail', function() {
+  runner.on(Runner.constants.RUNNER_EVENT_FAIL, function() {
     if (++n % width === 0) {
       process.stdout.write('\n  ');
     }
     process.stdout.write(Base.color('fail', Base.symbols.bang));
   });
 
-  runner.once('end', function() {
+  runner.once(Runner.constants.RUNNER_EVENT_END, function() {
     console.log();
     self.epilogue();
   });
diff --git a/lib/reporters/html.js b/lib/reporters/html.js
index 71bc21e113..efca0819c3 100644
--- a/lib/reporters/html.js
+++ b/lib/reporters/html.js
@@ -12,6 +12,7 @@ var Base = require('./base');
 var utils = require('../utils');
 var Progress = require('../browser/progress');
 var escapeRe = require('escape-string-regexp');
+var Runner = require('../runner');
 var escape = utils.escape;
 
 /**
@@ -112,7 +113,7 @@ function HTML(runner) {
     progress.size(40);
   }
 
-  runner.on('suite', function(suite) {
+  runner.on(Runner.constants.RUNNER_EVENT_SUITE, function(suite) {
     if (suite.root) {
       return;
     }
@@ -139,7 +140,7 @@ function HTML(runner) {
     stack.shift();
   });
 
-  runner.on('pass', function(test) {
+  runner.on(Runner.constants.RUNNER_EVENT_PASS, function(test) {
     var url = self.testURL(test);
     var markup =
       '<li class="test pass %e"><h2>%e<span class="duration">%ems</span> ' +
@@ -152,7 +153,7 @@ function HTML(runner) {
     updateStats();
   });
 
-  runner.on('fail', function(test) {
+  runner.on(Runner.constants.RUNNER_EVENT_FAIL, function(test) {
     var el = fragment(
       '<li class="test fail"><h2>%e <a href="%e" class="replay">' +
         playIcon +
@@ -208,7 +209,7 @@ function HTML(runner) {
     updateStats();
   });
 
-  runner.on('pending', function(test) {
+  runner.on(Runner.constants.RUNNER_EVENT_PENDING, function(test) {
     var el = fragment(
       '<li class="test pass pending"><h2>%e</h2></li>',
       test.title
diff --git a/lib/reporters/json-stream.js b/lib/reporters/json-stream.js
index c05050227b..f77dc1430e 100644
--- a/lib/reporters/json-stream.js
+++ b/lib/reporters/json-stream.js
@@ -7,6 +7,7 @@
  */
 
 var Base = require('./base');
+var Runner = require('../runner');
 
 /**
  * Expose `JSONStream`.
@@ -29,22 +30,22 @@ function JSONStream(runner) {
   var self = this;
   var total = runner.total;
 
-  runner.once('start', function() {
+  runner.once(Runner.constants.RUNNER_EVENT_START, function() {
     writeEvent(['start', {total: total}]);
   });
 
-  runner.on('pass', function(test) {
+  runner.on(Runner.constants.RUNNER_EVENT_PASS, function(test) {
     writeEvent(['pass', clean(test)]);
   });
 
-  runner.on('fail', function(test, err) {
+  runner.on(Runner.constants.RUNNER_EVENT_FAIL, function(test, err) {
     test = clean(test);
     test.err = err.message;
     test.stack = err.stack || null;
     writeEvent(['fail', test]);
   });
 
-  runner.once('end', function() {
+  runner.once(Runner.constants.RUNNER_EVENT_END, function() {
     writeEvent(['end', self.stats]);
   });
 }
diff --git a/lib/reporters/json.js b/lib/reporters/json.js
index c5106d3a65..d35c076c06 100644
--- a/lib/reporters/json.js
+++ b/lib/reporters/json.js
@@ -7,6 +7,7 @@
  */
 
 var Base = require('./base');
+var Runner = require('../runner');
 
 /**
  * Expose `JSON`.
@@ -32,23 +33,23 @@ function JSONReporter(runner) {
   var failures = [];
   var passes = [];
 
-  runner.on('test end', function(test) {
+  runner.on(Runner.constants.RUNNER_EVENT_TEST_END, function(test) {
     tests.push(test);
   });
 
-  runner.on('pass', function(test) {
+  runner.on(Runner.constants.RUNNER_EVENT_PASS, function(test) {
     passes.push(test);
   });
 
-  runner.on('fail', function(test) {
+  runner.on(Runner.constants.RUNNER_EVENT_FAIL, function(test) {
     failures.push(test);
   });
 
-  runner.on('pending', function(test) {
+  runner.on(Runner.constants.RUNNER_EVENT_PENDING, function(test) {
     pending.push(test);
   });
 
-  runner.once('end', function() {
+  runner.once(Runner.constants.RUNNER_EVENT_END, function() {
     var obj = {
       stats: self.stats,
       tests: tests.map(clean),
diff --git a/lib/reporters/landing.js b/lib/reporters/landing.js
index a33267adeb..b2f3f2df89 100644
--- a/lib/reporters/landing.js
+++ b/lib/reporters/landing.js
@@ -7,6 +7,7 @@
  */
 
 var Base = require('./base');
+var Runner = require('../runner');
 var inherits = require('../utils').inherits;
 var cursor = Base.cursor;
 var color = Base.color;
@@ -60,12 +61,12 @@ function Landing(runner) {
     return '  ' + color('runway', buf);
   }
 
-  runner.on('start', function() {
+  runner.on(Runner.constants.RUNNER_EVENT_START, function() {
     stream.write('\n\n\n  ');
     cursor.hide();
   });
 
-  runner.on('test end', function(test) {
+  runner.on(Runner.constants.RUNNER_EVENT_TEST_END, function(test) {
     // check if the plane crashed
     var col = crashed === -1 ? ((width * ++n) / total) | 0 : crashed;
 
@@ -86,7 +87,7 @@ function Landing(runner) {
     stream.write('\u001b[0m');
   });
 
-  runner.once('end', function() {
+  runner.once(Runner.constants.RUNNER_EVENT_END, function() {
     cursor.show();
     console.log();
     self.epilogue();
diff --git a/lib/reporters/list.js b/lib/reporters/list.js
index 4e324b61c7..ba3bb678f5 100644
--- a/lib/reporters/list.js
+++ b/lib/reporters/list.js
@@ -7,6 +7,7 @@
  */
 
 var Base = require('./base');
+var Runner = require('../runner');
 var inherits = require('../utils').inherits;
 var color = Base.color;
 var cursor = Base.cursor;
@@ -32,7 +33,7 @@ function List(runner) {
   var self = this;
   var n = 0;
 
-  runner.on('start', function() {
+  runner.on(Runner.constants.RUNNER_EVENT_START, function() {
     console.log();
   });
 
@@ -40,12 +41,12 @@ function List(runner) {
     process.stdout.write(color('pass', '    ' + test.fullTitle() + ': '));
   });
 
-  runner.on('pending', function(test) {
+  runner.on(Runner.constants.RUNNER_EVENT_PENDING, function(test) {
     var fmt = color('checkmark', '  -') + color('pending', ' %s');
     console.log(fmt, test.fullTitle());
   });
 
-  runner.on('pass', function(test) {
+  runner.on(Runner.constants.RUNNER_EVENT_PASS, function(test) {
     var fmt =
       color('checkmark', '  ' + Base.symbols.ok) +
       color('pass', ' %s: ') +
@@ -54,12 +55,12 @@ function List(runner) {
     console.log(fmt, test.fullTitle(), test.duration);
   });
 
-  runner.on('fail', function(test) {
+  runner.on(Runner.constants.RUNNER_EVENT_FAIL, function(test) {
     cursor.CR();
     console.log(color('fail', '  %d) %s'), ++n, test.fullTitle());
   });
 
-  runner.once('end', self.epilogue.bind(self));
+  runner.once(Runner.constants.RUNNER_EVENT_END, self.epilogue.bind(self));
 }
 
 /**
diff --git a/lib/reporters/markdown.js b/lib/reporters/markdown.js
index 70926ac617..a67f7cad43 100644
--- a/lib/reporters/markdown.js
+++ b/lib/reporters/markdown.js
@@ -8,6 +8,7 @@
 
 var Base = require('./base');
 var utils = require('../utils');
+var Runner = require('../runner');
 
 /**
  * Constants
@@ -77,7 +78,7 @@ function Markdown(runner) {
 
   generateTOC(runner.suite);
 
-  runner.on('suite', function(suite) {
+  runner.on(Runner.constants.RUNNER_EVENT_SUITE, function(suite) {
     ++level;
     var slug = utils.slug(suite.fullTitle());
     buf += '<a name="' + slug + '"></a>' + '\n';
@@ -88,7 +89,7 @@ function Markdown(runner) {
     --level;
   });
 
-  runner.on('pass', function(test) {
+  runner.on(Runner.constants.RUNNER_EVENT_PASS, function(test) {
     var code = utils.clean(test.body);
     buf += test.title + '.\n';
     buf += '\n```js\n';
@@ -96,7 +97,7 @@ function Markdown(runner) {
     buf += '```\n\n';
   });
 
-  runner.once('end', function() {
+  runner.once(Runner.constants.RUNNER_EVENT_END, function() {
     process.stdout.write('# TOC\n');
     process.stdout.write(generateTOC(runner.suite));
     process.stdout.write(buf);
diff --git a/lib/reporters/min.js b/lib/reporters/min.js
index 3277ed3442..d7f4469dd8 100644
--- a/lib/reporters/min.js
+++ b/lib/reporters/min.js
@@ -7,6 +7,7 @@
  */
 
 var Base = require('./base');
+var Runner = require('../runner');
 var inherits = require('../utils').inherits;
 
 /**
@@ -27,14 +28,14 @@ exports = module.exports = Min;
 function Min(runner) {
   Base.call(this, runner);
 
-  runner.on('start', function() {
+  runner.on(Runner.constants.RUNNER_EVENT_START, function() {
     // clear screen
     process.stdout.write('\u001b[2J');
     // set cursor position
     process.stdout.write('\u001b[1;3H');
   });
 
-  runner.once('end', this.epilogue.bind(this));
+  runner.once(Runner.constants.RUNNER_EVENT_END, this.epilogue.bind(this));
 }
 
 /**
diff --git a/lib/reporters/nyan.js b/lib/reporters/nyan.js
index c91cd5ddf3..7f4707a93b 100644
--- a/lib/reporters/nyan.js
+++ b/lib/reporters/nyan.js
@@ -7,6 +7,7 @@
  */
 
 var Base = require('./base');
+var Runner = require('../runner');
 var inherits = require('../utils').inherits;
 
 /**
@@ -40,24 +41,24 @@ function NyanCat(runner) {
   this.trajectories = [[], [], [], []];
   this.trajectoryWidthMax = width - nyanCatWidth;
 
-  runner.on('start', function() {
+  runner.on(Runner.constants.RUNNER_EVENT_START, function() {
     Base.cursor.hide();
     self.draw();
   });
 
-  runner.on('pending', function() {
+  runner.on(Runner.constants.RUNNER_EVENT_PENDING, function() {
     self.draw();
   });
 
-  runner.on('pass', function() {
+  runner.on(Runner.constants.RUNNER_EVENT_PASS, function() {
     self.draw();
   });
 
-  runner.on('fail', function() {
+  runner.on(Runner.constants.RUNNER_EVENT_FAIL, function() {
     self.draw();
   });
 
-  runner.once('end', function() {
+  runner.once(Runner.constants.RUNNER_EVENT_END, function() {
     Base.cursor.show();
     for (var i = 0; i < self.numberOfLines; i++) {
       write('\n');
diff --git a/lib/reporters/progress.js b/lib/reporters/progress.js
index 5b174f0d5b..5ff9ac307b 100644
--- a/lib/reporters/progress.js
+++ b/lib/reporters/progress.js
@@ -7,6 +7,7 @@
  */
 
 var Base = require('./base');
+var Runner = require('../runner');
 var inherits = require('../utils').inherits;
 var color = Base.color;
 var cursor = Base.cursor;
@@ -53,13 +54,13 @@ function Progress(runner, options) {
   options.verbose = reporterOptions.verbose || false;
 
   // tests started
-  runner.on('start', function() {
+  runner.on(Runner.constants.RUNNER_EVENT_START, function() {
     console.log();
     cursor.hide();
   });
 
   // tests complete
-  runner.on('test end', function() {
+  runner.on(Runner.constants.RUNNER_EVENT_TEST_END, function() {
     complete++;
 
     var percent = complete / total;
@@ -85,7 +86,7 @@ function Progress(runner, options) {
 
   // tests are complete, output some stats
   // and the failures if any
-  runner.once('end', function() {
+  runner.once(Runner.constants.RUNNER_EVENT_END, function() {
     cursor.show();
     console.log();
     self.epilogue();
diff --git a/lib/reporters/spec.js b/lib/reporters/spec.js
index 82a438fba7..8a4a6e14c7 100644
--- a/lib/reporters/spec.js
+++ b/lib/reporters/spec.js
@@ -7,6 +7,7 @@
  */
 
 var Base = require('./base');
+var Runner = require('../runner');
 var inherits = require('../utils').inherits;
 var color = Base.color;
 
@@ -36,11 +37,11 @@ function Spec(runner) {
     return Array(indents).join('  ');
   }
 
-  runner.on('start', function() {
+  runner.on(Runner.constants.RUNNER_EVENT_START, function() {
     console.log();
   });
 
-  runner.on('suite', function(suite) {
+  runner.on(Runner.constants.RUNNER_EVENT_SUITE, function(suite) {
     ++indents;
     console.log(color('suite', '%s%s'), indent(), suite.title);
   });
@@ -52,12 +53,12 @@ function Spec(runner) {
     }
   });
 
-  runner.on('pending', function(test) {
+  runner.on(Runner.constants.RUNNER_EVENT_PENDING, function(test) {
     var fmt = indent() + color('pending', '  - %s');
     console.log(fmt, test.title);
   });
 
-  runner.on('pass', function(test) {
+  runner.on(Runner.constants.RUNNER_EVENT_PASS, function(test) {
     var fmt;
     if (test.speed === 'fast') {
       fmt =
@@ -75,11 +76,11 @@ function Spec(runner) {
     }
   });
 
-  runner.on('fail', function(test) {
+  runner.on(Runner.constants.RUNNER_EVENT_FAIL, function(test) {
     console.log(indent() + color('fail', '  %d) %s'), ++n, test.title);
   });
 
-  runner.once('end', self.epilogue.bind(self));
+  runner.once(Runner.constants.RUNNER_EVENT_END, self.epilogue.bind(self));
 }
 
 /**
diff --git a/lib/reporters/tap.js b/lib/reporters/tap.js
index 4c7c15a864..277c5fa3ee 100644
--- a/lib/reporters/tap.js
+++ b/lib/reporters/tap.js
@@ -8,6 +8,7 @@
 
 var util = require('util');
 var Base = require('./base');
+var Runner = require('../runner');
 var inherits = require('../utils').inherits;
 var sprintf = util.format;
 
@@ -42,29 +43,29 @@ function TAP(runner, options) {
 
   this._producer = createProducer(tapVersion);
 
-  runner.once('start', function() {
+  runner.once(Runner.constants.RUNNER_EVENT_START, function() {
     var ntests = runner.grepTotal(runner.suite);
     self._producer.writeVersion();
     self._producer.writePlan(ntests);
   });
 
-  runner.on('test end', function() {
+  runner.on(Runner.constants.RUNNER_EVENT_TEST_END, function() {
     ++n;
   });
 
-  runner.on('pending', function(test) {
+  runner.on(Runner.constants.RUNNER_EVENT_PENDING, function(test) {
     self._producer.writePending(n, test);
   });
 
-  runner.on('pass', function(test) {
+  runner.on(Runner.constants.RUNNER_EVENT_PASS, function(test) {
     self._producer.writePass(n, test);
   });
 
-  runner.on('fail', function(test, err) {
+  runner.on(Runner.constants.RUNNER_EVENT_FAIL, function(test, err) {
     self._producer.writeFail(n, test, err);
   });
 
-  runner.once('end', function() {
+  runner.once(Runner.constants.RUNNER_EVENT_END, function() {
     self._producer.writeEpilogue(runner.stats);
   });
 }
diff --git a/lib/reporters/xunit.js b/lib/reporters/xunit.js
index 643367aa9d..b23d10e436 100644
--- a/lib/reporters/xunit.js
+++ b/lib/reporters/xunit.js
@@ -8,6 +8,7 @@
 
 var Base = require('./base');
 var utils = require('../utils');
+var Runner = require('../runner');
 var inherits = utils.inherits;
 var fs = require('fs');
 var escape = utils.escape;
@@ -65,19 +66,19 @@ function XUnit(runner, options) {
   // fall back to the default suite name
   suiteName = suiteName || DEFAULT_SUITE_NAME;
 
-  runner.on('pending', function(test) {
+  runner.on(Runner.constants.RUNNER_EVENT_PENDING, function(test) {
     tests.push(test);
   });
 
-  runner.on('pass', function(test) {
+  runner.on(Runner.constants.RUNNER_EVENT_PASS, function(test) {
     tests.push(test);
   });
 
-  runner.on('fail', function(test) {
+  runner.on(Runner.constants.RUNNER_EVENT_FAIL, function(test) {
     tests.push(test);
   });
 
-  runner.once('end', function() {
+  runner.once(Runner.constants.RUNNER_EVENT_END, function() {
     self.write(
       tag(
         'testsuite',
diff --git a/lib/runner.js b/lib/runner.js
index 604d79b495..2c5210c1c8 100644
--- a/lib/runner.js
+++ b/lib/runner.js
@@ -12,7 +12,7 @@ var utils = require('./utils');
 var inherits = utils.inherits;
 var debug = require('debug')('mocha:runner');
 var Runnable = require('./runnable');
-var createStatsCollector = require('./stats-collector');
+var Suite = require('./suite');
 var stackFilter = utils.stackTraceFilter();
 var stringify = utils.stringify;
 var type = utils.type;
@@ -55,6 +55,7 @@ module.exports = Runner;
  *   - `pass`  (test) test passed
  *   - `fail`  (test, err) test failed
  *   - `pending`  (test) test pending
+ *   - `retry`  (test) test will retry after failure
  *
  * @memberof Mocha
  * @public
@@ -72,16 +73,15 @@ function Runner(suite, delay) {
   this.started = false;
   this.total = suite.total();
   this.failures = 0;
-  this.on('test end', function(test) {
+  this.on(constants.RUNNER_EVENT_TEST_END, function(test) {
     self.checkGlobals(test);
   });
-  this.on('hook end', function(hook) {
+  this.on(constants.RUNNER_EVENT_HOOK_END, function(hook) {
     self.checkGlobals(hook);
   });
   this._defaultGrep = /.*/;
   this.grep(this._defaultGrep);
   this.globals(this.globalProps().concat(extraGlobals()));
-  createStatsCollector(this);
 }
 
 /**
@@ -227,7 +227,7 @@ Runner.prototype.fail = function(test, err) {
   }
 
   ++this.failures;
-  test.state = 'failed';
+  test.state = constants.RUNNER_STATE_FAILED;
 
   if (!isError(err)) {
     err = thrown2Error(err);
@@ -240,7 +240,7 @@ Runner.prototype.fail = function(test, err) {
     // some environments do not take kindly to monkeying with the stack
   }
 
-  this.emit('fail', test, err);
+  this.emit(constants.RUNNER_EVENT_FAIL, test, err);
 };
 
 /**
@@ -284,7 +284,7 @@ Runner.prototype.failHook = function(hook, err) {
 
 Runner.prototype.hook = function(name, fn) {
   var suite = this.suite;
-  var hooks = suite['_' + name];
+  var hooks = suite.getHooks(name);
   var self = this;
 
   function next(i) {
@@ -296,7 +296,7 @@ Runner.prototype.hook = function(name, fn) {
 
     hook.ctx.currentTest = self.test;
 
-    self.emit('hook', hook);
+    self.emit(constants.RUNNER_EVENT_HOOK, hook);
 
     if (!hook.listeners('error').length) {
       hook.on('error', function(err) {
@@ -311,7 +311,10 @@ Runner.prototype.hook = function(name, fn) {
       }
       if (err) {
         if (err instanceof Pending) {
-          if (name === 'beforeEach' || name === 'afterEach') {
+          if (
+            name === Suite.constants.SUITE_HOOK_BEFORE_EACH ||
+            name === Suite.constants.SUITE_HOOK_AFTER_EACH
+          ) {
             self.test.pending = true;
           } else {
             suite.tests.forEach(function(test) {
@@ -330,7 +333,7 @@ Runner.prototype.hook = function(name, fn) {
           return fn(err);
         }
       }
-      self.emit('hook end', hook);
+      self.emit(constants.RUNNER_EVENT_HOOK_END, hook);
       delete hook.ctx.currentTest;
       next(++i);
     });
@@ -473,7 +476,10 @@ Runner.prototype.runTests = function(suite, fn) {
 
     if (self.suite) {
       // call hookUp afterEach
-      self.hookUp('afterEach', function(err2, errSuite2) {
+      self.hookUp(Suite.constants.SUITE_HOOK_AFTER_EACH, function(
+        err2,
+        errSuite2
+      ) {
         self.suite = orig;
         // some hooks may fail even now
         if (err2) {
@@ -539,24 +545,27 @@ Runner.prototype.runTests = function(suite, fn) {
         self.fail(test, new Error('Pending test forbidden'));
         delete test.isPending;
       } else {
-        self.emit('pending', test);
+        self.emit(constants.RUNNER_EVENT_PENDING, test);
       }
-      self.emit('test end', test);
+      self.emit(constants.RUNNER_EVENT_TEST_END, test);
       return next();
     }
 
     // execute test and hook(s)
-    self.emit('test', (self.test = test));
-    self.hookDown('beforeEach', function(err, errSuite) {
+    self.emit(constants.RUNNER_EVENT_TEST, (self.test = test));
+    self.hookDown(Suite.constants.SUITE_HOOK_BEFORE_EACH, function(
+      err,
+      errSuite
+    ) {
       if (test.isPending()) {
         if (self.forbidPending) {
           test.isPending = alwaysFalse;
           self.fail(test, new Error('Pending test forbidden'));
           delete test.isPending;
         } else {
-          self.emit('pending', test);
+          self.emit(constants.RUNNER_EVENT_PENDING, test);
         }
-        self.emit('test end', test);
+        self.emit(constants.RUNNER_EVENT_TEST_END, test);
         return next();
       }
       if (err) {
@@ -571,33 +580,33 @@ Runner.prototype.runTests = function(suite, fn) {
             self.fail(test, new Error('Pending test forbidden'));
           } else if (err instanceof Pending) {
             test.pending = true;
-            self.emit('pending', test);
+            self.emit(constants.RUNNER_EVENT_PENDING, test);
           } else if (retry < test.retries()) {
             var clonedTest = test.clone();
             clonedTest.currentRetry(retry + 1);
             tests.unshift(clonedTest);
 
-            self.emit('retry', test, err);
+            self.emit(constants.RUNNER_EVENT_RETRY, test, err);
 
             // Early return + hook trigger so that it doesn't
             // increment the count wrong
-            return self.hookUp('afterEach', next);
+            return self.hookUp(Suite.constants.SUITE_HOOK_AFTER_EACH, next);
           } else {
             self.fail(test, err);
           }
-          self.emit('test end', test);
+          self.emit(constants.RUNNER_EVENT_TEST_END, test);
 
           if (err instanceof Pending) {
             return next();
           }
 
-          return self.hookUp('afterEach', next);
+          return self.hookUp(Suite.constants.SUITE_HOOK_AFTER_EACH, next);
         }
 
-        test.state = 'passed';
-        self.emit('pass', test);
-        self.emit('test end', test);
-        self.hookUp('afterEach', next);
+        test.state = constants.RUNNER_STATE_PASSED;
+        self.emit(constants.RUNNER_EVENT_PASS, test);
+        self.emit(constants.RUNNER_EVENT_TEST_END, test);
+        self.hookUp(Suite.constants.SUITE_HOOK_AFTER_EACH, next);
       });
     });
   }
@@ -630,7 +639,7 @@ Runner.prototype.runSuite = function(suite, fn) {
     return fn();
   }
 
-  this.emit('suite', (this.suite = suite));
+  this.emit(constants.RUNNER_EVENT_SUITE, (this.suite = suite));
 
   function next(errSuite) {
     if (errSuite) {
@@ -680,8 +689,8 @@ Runner.prototype.runSuite = function(suite, fn) {
       // remove reference to test
       delete self.test;
 
-      self.hook('afterAll', function() {
-        self.emit('suite end', suite);
+      self.hook(Suite.constants.SUITE_HOOK_AFTER_ALL, function() {
+        self.emit(constants.RUNNER_EVENT_SUITE_END, suite);
         fn(errSuite);
       });
     }
@@ -689,7 +698,7 @@ Runner.prototype.runSuite = function(suite, fn) {
 
   this.nextSuite = next;
 
-  this.hook('beforeAll', function(err) {
+  this.hook(Suite.constants.SUITE_HOOK_BEFORE_ALL, function(err) {
     if (err) {
       return done();
     }
@@ -734,9 +743,9 @@ Runner.prototype.uncaught = function(err) {
       this.fail(runnable, err);
     } else {
       // Can't recover from this failure
-      this.emit('start');
+      this.emit(constants.RUNNER_EVENT_START);
       this.fail(runnable, err);
-      this.emit('end');
+      this.emit(constants.RUNNER_EVENT_END);
     }
 
     return;
@@ -756,14 +765,16 @@ Runner.prototype.uncaught = function(err) {
   this.fail(runnable, err);
   if (!alreadyPassed) {
     // recover from test
-    if (runnable.type === 'test') {
-      this.emit('test end', runnable);
-      this.hookUp('afterEach', this.next);
+    if (runnable.type === constants.RUNNER_EVENT_TEST) {
+      this.emit(constants.RUNNER_EVENT_TEST_END, runnable);
+      this.hookUp(Suite.constants.SUITE_HOOK_AFTER_EACH, this.next);
       return;
     }
 
     // recover from hooks
     var errSuite = this.suite;
+
+    // XXX how about a less awful way to determine this?
     // if hook failure is in afterEach block
     if (runnable.fullTitle().indexOf('after each') > -1) {
       return this.hookErr(err, errSuite, true);
@@ -777,47 +788,9 @@ Runner.prototype.uncaught = function(err) {
   }
 
   // bail
-  this.emit('end');
+  this.emit(constants.RUNNER_EVENT_END);
 };
 
-/**
- * Cleans up the references to all the deferred functions
- * (before/after/beforeEach/afterEach) and tests of a Suite.
- * These must be deleted otherwise a memory leak can happen,
- * as those functions may reference variables from closures,
- * thus those variables can never be garbage collected as long
- * as the deferred functions exist.
- *
- * @param {Suite} suite
- */
-function cleanSuiteReferences(suite) {
-  function cleanArrReferences(arr) {
-    for (var i = 0; i < arr.length; i++) {
-      delete arr[i].fn;
-    }
-  }
-
-  if (Array.isArray(suite._beforeAll)) {
-    cleanArrReferences(suite._beforeAll);
-  }
-
-  if (Array.isArray(suite._beforeEach)) {
-    cleanArrReferences(suite._beforeEach);
-  }
-
-  if (Array.isArray(suite._afterAll)) {
-    cleanArrReferences(suite._afterAll);
-  }
-
-  if (Array.isArray(suite._afterEach)) {
-    cleanArrReferences(suite._afterEach);
-  }
-
-  for (var i = 0; i < suite.tests.length; i++) {
-    delete suite.tests[i].fn;
-  }
-}
-
 /**
  * Run the root suite and invoke `fn(failures)`
  * on completion.
@@ -844,25 +817,27 @@ Runner.prototype.run = function(fn) {
     }
     self.started = true;
     Runner.immediately(function() {
-      self.emit('start');
+      self.emit(constants.RUNNER_EVENT_START);
     });
 
     self.runSuite(rootSuite, function() {
       debug('finished running');
       Runner.immediately(function() {
-        self.emit('end');
+        self.emit(constants.RUNNER_EVENT_END);
       });
     });
   }
 
-  debug('start');
+  debug(constants.RUNNER_EVENT_START);
 
   // references cleanup to avoid memory leaks
-  this.on('suite end', cleanSuiteReferences);
+  this.on(constants.RUNNER_EVENT_SUITE_END, function(suite) {
+    suite.cleanReferences();
+  });
 
   // callback
-  this.on('end', function() {
-    debug('end');
+  this.on(constants.RUNNER_EVENT_END, function() {
+    debug(constants.RUNNER_EVENT_END);
     process.removeListener('uncaughtException', uncaught);
     fn(self.failures);
   });
@@ -873,8 +848,8 @@ Runner.prototype.run = function(fn) {
   if (this._delay) {
     // for reporters, I guess.
     // might be nice to debounce some dots while we wait.
-    this.emit('waiting', rootSuite);
-    rootSuite.once('run', start);
+    this.emit(constants.RUNNER_EVENT_WAITING, rootSuite);
+    rootSuite.once(Suite.constants.SUITE_EVENT_RUN, start);
   } else {
     start();
   }
@@ -1017,6 +992,8 @@ function thrown2Error(err) {
  * Array of globals dependent on the environment.
  *
  * @return {Array}
+ * @deprecated
+ * @todo remove; long since unsupported
  * @private
  */
 function extraGlobals() {
@@ -1027,7 +1004,6 @@ function extraGlobals() {
     });
 
     // 'errno' was renamed to process._errno in v0.9.11.
-
     if (nodeVersion < 0x00090b) {
       return ['errno'];
     }
@@ -1035,3 +1011,27 @@ function extraGlobals() {
 
   return [];
 }
+
+/**
+ * Constants used by Runner
+ * @public
+ */
+var constants = Object.freeze({
+  RUNNER_EVENT_END: 'end',
+  RUNNER_EVENT_FAIL: 'fail',
+  RUNNER_EVENT_HOOK: 'hook',
+  RUNNER_EVENT_HOOK_END: 'hook end',
+  RUNNER_EVENT_PASS: 'pass',
+  RUNNER_EVENT_PENDING: 'pending',
+  RUNNER_EVENT_RETRY: 'retry',
+  RUNNER_EVENT_START: 'start',
+  RUNNER_EVENT_SUITE: 'suite',
+  RUNNER_EVENT_SUITE_END: 'suite end',
+  RUNNER_EVENT_TEST: 'test',
+  RUNNER_EVENT_TEST_END: 'test end',
+  RUNNER_EVENT_WAITING: 'waiting',
+  RUNNER_STATE_FAILED: 'failed',
+  RUNNER_STATE_PASSED: 'passed'
+});
+
+module.exports.constants = constants;
diff --git a/lib/stats-collector.js b/lib/stats-collector.js
index 7a5b3fc61f..0c4347fc45 100644
--- a/lib/stats-collector.js
+++ b/lib/stats-collector.js
@@ -6,6 +6,8 @@
  * @module
  */
 
+var Runner = require('./runner');
+
 /**
  * Test statistics collector.
  *
@@ -48,31 +50,31 @@ function createStatsCollector(runner) {
 
   runner.stats = stats;
 
-  runner.once('start', function() {
+  runner.once(Runner.constants.RUNNER_EVENT_START, function() {
     stats.start = new Date();
   });
 
-  runner.on('suite', function(suite) {
+  runner.on(Runner.constants.RUNNER_EVENT_SUITE, function(suite) {
     suite.root || stats.suites++;
   });
 
-  runner.on('pass', function() {
+  runner.on(Runner.constants.RUNNER_EVENT_PASS, function() {
     stats.passes++;
   });
 
-  runner.on('fail', function() {
+  runner.on(Runner.constants.RUNNER_EVENT_FAIL, function() {
     stats.failures++;
   });
 
-  runner.on('pending', function() {
+  runner.on(Runner.constants.RUNNER_EVENT_PENDING, function() {
     stats.pending++;
   });
 
-  runner.on('test end', function() {
+  runner.on(Runner.constants.RUNNER_EVENT_TEST_END, function() {
     stats.tests++;
   });
 
-  runner.once('end', function() {
+  runner.once(Runner.constants.RUNNER_EVENT_END, function() {
     stats.end = new Date();
     stats.duration = stats.end - stats.start;
   });
diff --git a/lib/suite.js b/lib/suite.js
index 64e7db4b24..040bff109c 100644
--- a/lib/suite.js
+++ b/lib/suite.js
@@ -241,7 +241,7 @@ Suite.prototype.beforeAll = function(title, fn) {
 
   var hook = this._createHook(title, fn);
   this._beforeAll.push(hook);
-  this.emit('beforeAll', hook);
+  this.emit(constants.SUITE_EVENT_BEFORE_ALL, hook);
   return this;
 };
 
@@ -265,7 +265,7 @@ Suite.prototype.afterAll = function(title, fn) {
 
   var hook = this._createHook(title, fn);
   this._afterAll.push(hook);
-  this.emit('afterAll', hook);
+  this.emit(constants.SUITE_EVENT_AFTER_ALL, hook);
   return this;
 };
 
@@ -289,7 +289,7 @@ Suite.prototype.beforeEach = function(title, fn) {
 
   var hook = this._createHook(title, fn);
   this._beforeEach.push(hook);
-  this.emit('beforeEach', hook);
+  this.emit(constants.SUITE_EVENT_BEFORE_EACH, hook);
   return this;
 };
 
@@ -313,7 +313,7 @@ Suite.prototype.afterEach = function(title, fn) {
 
   var hook = this._createHook(title, fn);
   this._afterEach.push(hook);
-  this.emit('afterEach', hook);
+  this.emit(constants.SUITE_EVENT_AFTER_EACH, hook);
   return this;
 };
 
@@ -332,7 +332,7 @@ Suite.prototype.addSuite = function(suite) {
   suite.slow(this.slow());
   suite.bail(this.bail());
   this.suites.push(suite);
-  this.emit('suite', suite);
+  this.emit(constants.SUITE_EVENT_SUITE, suite);
   return this;
 };
 
@@ -351,7 +351,7 @@ Suite.prototype.addTest = function(test) {
   test.slow(this.slow());
   test.ctx = this.ctx;
   this.tests.push(test);
-  this.emit('test', test);
+  this.emit(constants.SUITE_EVENT_TEST, test);
   return this;
 };
 
@@ -422,6 +422,79 @@ Suite.prototype.eachTest = function(fn) {
  */
 Suite.prototype.run = function run() {
   if (this.root) {
-    this.emit('run');
+    this.emit(constants.SUITE_EVENT_RUN);
   }
 };
+
+/**
+ * Returns the array of hooks by hook name; see `SUITE_HOOK_*` constants.
+ * @private
+ */
+Suite.prototype.getHooks = function getHooks(name) {
+  return this['_' + name];
+};
+
+/**
+ * Cleans up the references to all the deferred functions
+ * (before/after/beforeEach/afterEach) and tests of a Suite.
+ * These must be deleted otherwise a memory leak can happen,
+ * as those functions may reference variables from closures,
+ * thus those variables can never be garbage collected as long
+ * as the deferred functions exist.
+ *
+ * @private
+ */
+Suite.prototype.cleanReferences = function cleanReferences() {
+  function cleanArrReferences(arr) {
+    for (var i = 0; i < arr.length; i++) {
+      delete arr[i].fn;
+    }
+  }
+
+  if (Array.isArray(this._beforeAll)) {
+    cleanArrReferences(this._beforeAll);
+  }
+
+  if (Array.isArray(this._beforeEach)) {
+    cleanArrReferences(this._beforeEach);
+  }
+
+  if (Array.isArray(this._afterAll)) {
+    cleanArrReferences(this._afterAll);
+  }
+
+  if (Array.isArray(this._afterEach)) {
+    cleanArrReferences(this._afterEach);
+  }
+
+  for (var i = 0; i < this.tests.length; i++) {
+    delete this.tests[i].fn;
+  }
+};
+
+/**
+ * Constants used by Suite
+ * @public
+ */
+var constants = Object.freeze({
+  SUITE_EVENT_POST_REQUIRE: 'post-require',
+  SUITE_EVENT_PRE_REQUIRE: 'pre-require',
+  SUITE_EVENT_REQUIRE: 'require',
+  SUITE_EVENT_RUN: 'run',
+  SUITE_HOOK_BEFORE_ALL: 'beforeAll',
+  SUITE_HOOK_BEFORE_EACH: 'beforeEach',
+  SUITE_HOOK_AFTER_ALL: 'afterAll',
+  SUITE_HOOK_AFTER_EACH: 'afterEach',
+
+  // XXX these are all unused and need to be removed.
+  // they've existed since time immemorial, so probably safe to consider
+  // removal to be a breaking change.
+  SUITE_EVENT_AFTER_ALL: 'afterAll',
+  SUITE_EVENT_AFTER_EACH: 'afterEach',
+  SUITE_EVENT_BEFORE_ALL: 'beforeAll',
+  SUITE_EVENT_BEFORE_EACH: 'beforeEach',
+  SUITE_EVENT_SUITE: 'suite',
+  SUITE_EVENT_TEST: 'test'
+});
+
+module.exports.constants = constants;
diff --git a/test/integration/fixtures/regression/1794/simple-ui.js b/test/integration/fixtures/regression/1794/simple-ui.fixture.js
similarity index 63%
rename from test/integration/fixtures/regression/1794/simple-ui.js
rename to test/integration/fixtures/regression/1794/simple-ui.fixture.js
index b27c623003..70d18b0196 100644
--- a/test/integration/fixtures/regression/1794/simple-ui.js
+++ b/test/integration/fixtures/regression/1794/simple-ui.fixture.js
@@ -1,15 +1,22 @@
 'use strict';
 
-var path = '../../../../../lib/';
-var Mocha = require(path + 'mocha');
-var Test = require(path + 'test');
+var Mocha = require('../../../../../lib/mocha');
+var Test = Mocha.Test;
+var Suite = Mocha.Suite;
 
 /**
  * A simple UI that only exposes a single function: test
  */
 module.exports = Mocha.interfaces['simple-ui'] = function(suite) {
-  suite.on('pre-require', function(context, file, mocha) {
-    var common = require(path + 'interfaces/common')([suite], context);
+  suite.on(Suite.constants.SUITE_EVENT_PRE_REQUIRE, function(
+    context,
+    file,
+    mocha
+  ) {
+    var common = require('../../../../../lib/interfaces/common')(
+      [suite],
+      context
+    );
 
     context.run = mocha.options.delay && common.runWithSuite(suite);
 
diff --git a/test/integration/fixtures/simple-reporter.fixture.js b/test/integration/fixtures/simple-reporter.fixture.js
new file mode 100644
index 0000000000..f5b5b5d76f
--- /dev/null
+++ b/test/integration/fixtures/simple-reporter.fixture.js
@@ -0,0 +1,30 @@
+'use strict';
+
+var Base = require('../../../lib/reporters/base');
+var Runner = require('../../../lib/runner');
+
+module.exports = SimpleReporter;
+
+function SimpleReporter(runner) {
+  Base.call(this, runner);
+
+  runner.on(Runner.constants.RUNNER_EVENT_SUITE, function(suite) {
+    console.log("on('suite') called");
+  });
+
+  runner.on(Runner.constants.RUNNER_EVENT_FAIL, function(test, err) {
+    console.log("on('fail') called");
+  });
+
+  runner.on(Runner.constants.RUNNER_EVENT_PASS, function(test) {
+    console.log("on('pass') called");
+  });
+
+  runner.on(Runner.constants.RUNNER_EVENT_TEST_END, function(test, err) {
+    console.log("on('test end') called");
+  });
+
+  runner.on(Runner.constants.RUNNER_EVENT_END, function() {
+    console.log("on('end') called");
+  });
+}
diff --git a/test/integration/fixtures/simple-reporter.js b/test/integration/fixtures/simple-reporter.js
deleted file mode 100644
index d066a84304..0000000000
--- a/test/integration/fixtures/simple-reporter.js
+++ /dev/null
@@ -1,28 +0,0 @@
-'use strict';
-
-var baseReporter = require('../../../lib/reporters/base');
-module.exports = simplereporter;
-
-function simplereporter(runner) {
-  baseReporter.call(this, runner);
-
-  runner.on('suite', function(suite) {
-    console.log("on('suite') called");
-  });
-
-  runner.on('fail', function(test, err) {
-    console.log("on('fail') called");
-  });
-
-  runner.on('pass', function(test) {
-    console.log("on('pass') called");
-  });
-
-  runner.on('test end', function(test, err) {
-    console.log("on('test end') called");
-  });
-
-  runner.on('end', function() {
-    console.log("on('end') called");
-  });
-}
diff --git a/test/integration/helpers.js b/test/integration/helpers.js
index 0680faa017..06baa0c2fb 100644
--- a/test/integration/helpers.js
+++ b/test/integration/helpers.js
@@ -3,7 +3,7 @@
 var format = require('util').format;
 var spawn = require('cross-spawn').spawn;
 var path = require('path');
-var baseReporter = require('../../lib/reporters/base');
+var Base = require('../../lib/reporters/base');
 
 module.exports = {
   /**
@@ -132,7 +132,7 @@ module.exports = {
   /**
    * regular expression used for splitting lines based on new line / dot symbol.
    */
-  splitRegExp: new RegExp('[\\n' + baseReporter.symbols.dot + ']+'),
+  splitRegExp: new RegExp('[\\n' + Base.symbols.dot + ']+'),
 
   /**
    * Invokes the mocha binary. Accepts an array of additional command line args
diff --git a/test/integration/regression.spec.js b/test/integration/regression.spec.js
index 566ccc7cd8..b122311383 100644
--- a/test/integration/regression.spec.js
+++ b/test/integration/regression.spec.js
@@ -31,7 +31,7 @@ describe('regressions', function() {
       'fixtures',
       'regression',
       '1794',
-      'simple-ui.js'
+      'simple-ui.fixture.js'
     );
     var args = ['--require', simpleUiPath, '--ui', 'simple-ui'];
     run('regression/1794/issue-1794.fixture.js', args, function(err, res) {
diff --git a/test/integration/reporters.spec.js b/test/integration/reporters.spec.js
index c78da8ab6b..3d864091fe 100644
--- a/test/integration/reporters.spec.js
+++ b/test/integration/reporters.spec.js
@@ -66,7 +66,7 @@ describe('reporters', function() {
   describe('loader', function() {
     it('loads a reporter from a path relative to the current working directory', function(done) {
       var reporterAtARelativePath =
-        'test/integration/fixtures/simple-reporter.js';
+        'test/integration/fixtures/simple-reporter.fixture.js';
 
       var args = ['--reporter=' + reporterAtARelativePath];
 
@@ -84,7 +84,7 @@ describe('reporters', function() {
       // Generates an absolute path string
       var reporterAtAnAbsolutePath = path.join(
         process.cwd(),
-        'test/integration/fixtures/simple-reporter.js'
+        'test/integration/fixtures/simple-reporter.fixture.js'
       );
 
       var args = ['--reporter=' + reporterAtAnAbsolutePath];
diff --git a/test/jsapi/index.js b/test/jsapi/index.js
index beac56864b..fb2d4b5c5e 100644
--- a/test/jsapi/index.js
+++ b/test/jsapi/index.js
@@ -1,6 +1,7 @@
 'use strict';
 
 var Mocha = require('../../');
+var Runner = Mocha.Runner;
 
 var mocha = new Mocha({
   ui: 'bdd',
@@ -25,6 +26,6 @@ mocha
   .run(function() {
     console.log('done');
   })
-  .on('pass', function(test) {
+  .on(Runner.constants.RUNNER_EVENT_PASS, function(test) {
     // console.log('... %s', test.title);
   });
diff --git a/test/unit/runner.spec.js b/test/unit/runner.spec.js
index e89ef2b2d6..78dc188279 100644
--- a/test/unit/runner.spec.js
+++ b/test/unit/runner.spec.js
@@ -7,6 +7,7 @@ var Test = mocha.Test;
 var Hook = mocha.Hook;
 var path = require('path');
 var noop = mocha.utils.noop;
+var constants = Runner.constants;
 
 describe('Runner', function() {
   var suite;
@@ -103,7 +104,7 @@ describe('Runner', function() {
       var test = new Test('im a test', noop);
       runner.checkGlobals();
       global.foo = 'bar';
-      runner.on('fail', function(_test, err) {
+      runner.on(constants.RUNNER_EVENT_FAIL, function(_test, err) {
         expect(_test, 'to be', test);
         expect(err.message, 'to be', 'global leak detected: foo');
         delete global.foo;
@@ -116,7 +117,7 @@ describe('Runner', function() {
       var doneCalled = false;
       runner.globals('good');
       global.bad = 1;
-      runner.on('fail', function() {
+      runner.on(constants.RUNNER_EVENT_FAIL, function() {
         delete global.bad;
         done();
         doneCalled = true;
@@ -157,7 +158,7 @@ describe('Runner', function() {
       runner.checkGlobals();
       global.foo = 'bar';
       global.bar = 'baz';
-      runner.on('fail', function(_test, err) {
+      runner.on(constants.RUNNER_EVENT_FAIL, function(_test, err) {
         expect(_test, 'to be', test);
         expect(err.message, 'to be', 'global leaks detected: foo, bar');
         delete global.foo;
@@ -191,7 +192,7 @@ describe('Runner', function() {
 
       global.foo = 'bar';
       global.bar = 'baz';
-      runner.on('fail', function(test, err) {
+      runner.on(constants.RUNNER_EVENT_FAIL, function(test, err) {
         expect(test.title, 'to be', 'im a test about lions');
         expect(err.message, 'to be', 'global leak detected: bar');
         delete global.foo;
@@ -202,7 +203,7 @@ describe('Runner', function() {
 
     it('should emit "fail" when a global beginning with d is introduced', function(done) {
       global.derp = 'bar';
-      runner.on('fail', function() {
+      runner.on(constants.RUNNER_EVENT_FAIL, function() {
         delete global.derp;
         done();
       });
@@ -242,7 +243,7 @@ describe('Runner', function() {
     it('should emit "fail"', function(done) {
       var test = new Test('some other test', noop);
       var err = {};
-      runner.on('fail', function(test, err) {
+      runner.on(constants.RUNNER_EVENT_FAIL, function(test, err) {
         expect(test, 'to be', test);
         expect(err, 'to be', err);
         done();
@@ -253,7 +254,7 @@ describe('Runner', function() {
     it('should emit a helpful message when failed with a string', function(done) {
       var test = new Test('helpful test', noop);
       var err = 'string';
-      runner.on('fail', function(test, err) {
+      runner.on(constants.RUNNER_EVENT_FAIL, function(test, err) {
         expect(
           err.message,
           'to be',
@@ -267,7 +268,7 @@ describe('Runner', function() {
     it('should emit a the error when failed with an Error instance', function(done) {
       var test = new Test('a test', noop);
       var err = new Error('an error message');
-      runner.on('fail', function(test, err) {
+      runner.on(constants.RUNNER_EVENT_FAIL, function(test, err) {
         expect(err.message, 'to be', 'an error message');
         done();
       });
@@ -277,7 +278,7 @@ describe('Runner', function() {
     it('should emit the error when failed with an Error-like object', function(done) {
       var test = new Test('a test', noop);
       var err = {message: 'an error message'};
-      runner.on('fail', function(test, err) {
+      runner.on(constants.RUNNER_EVENT_FAIL, function(test, err) {
         expect(err.message, 'to be', 'an error message');
         done();
       });
@@ -287,7 +288,7 @@ describe('Runner', function() {
     it('should emit a helpful message when failed with an Object', function(done) {
       var test = new Test('a test', noop);
       var err = {x: 1};
-      runner.on('fail', function(test, err) {
+      runner.on(constants.RUNNER_EVENT_FAIL, function(test, err) {
         expect(
           err.message,
           'to be',
@@ -301,7 +302,7 @@ describe('Runner', function() {
     it('should emit a helpful message when failed with an Array', function(done) {
       var test = new Test('a test', noop);
       var err = [1, 2];
-      runner.on('fail', function(test, err) {
+      runner.on(constants.RUNNER_EVENT_FAIL, function(test, err) {
         expect(
           err.message,
           'to be',
@@ -324,7 +325,7 @@ describe('Runner', function() {
       });
       var test = new Test('a test', noop);
 
-      runner.on('fail', function(test, err) {
+      runner.on(constants.RUNNER_EVENT_FAIL, function(test, err) {
         expect(err.message, 'to be', 'not evil');
         done();
       });
@@ -365,7 +366,7 @@ describe('Runner', function() {
     it('should emit "fail"', function(done) {
       var hook = new Hook();
       var err = {};
-      runner.on('fail', function(hook, err) {
+      runner.on(constants.RUNNER_EVENT_FAIL, function(hook, err) {
         expect(hook, 'to be', hook);
         expect(err, 'to be', err);
         done();
@@ -377,7 +378,7 @@ describe('Runner', function() {
       var hook = new Hook();
       var err = {};
       suite.bail(false);
-      runner.on('end', function() {
+      runner.on(constants.RUNNER_EVENT_END, function() {
         throw new Error('"end" was emit, but the bail is false');
       });
       runner.failHook(hook, err);
@@ -400,7 +401,7 @@ describe('Runner', function() {
       suite.retries(retries);
       suite.addTest(test);
 
-      runner.on('retry', function(testClone, testErr) {
+      runner.on(constants.RUNNER_EVENT_RETRY, function(testClone, testErr) {
         retryableFails += 1;
         expect(testClone.title, 'to be', test.title);
         expect(testErr, 'to be', err);
@@ -458,7 +459,7 @@ describe('Runner', function() {
         // Fake stack-trace
         err.stack = stack.join('\n');
 
-        runner.on('fail', function(hook, err) {
+        runner.on(constants.RUNNER_EVENT_FAIL, function(hook, err) {
           expect(err.stack, 'to be', stack.slice(0, 3).join('\n'));
           done();
         });
@@ -481,7 +482,7 @@ describe('Runner', function() {
         // Add --stack-trace option
         runner.fullStackTrace = true;
 
-        runner.on('fail', function(hook, err) {
+        runner.on(constants.RUNNER_EVENT_FAIL, function(hook, err) {
           expect(err.stack, 'to be', stack.join('\n'));
           done();
         });
diff --git a/test/unit/throw.spec.js b/test/unit/throw.spec.js
index 66021d3d38..404f9b8b83 100644
--- a/test/unit/throw.spec.js
+++ b/test/unit/throw.spec.js
@@ -33,7 +33,7 @@ describe('a test that throws', function() {
       });
       suite.addTest(test);
       runner = new Runner(suite);
-      runner.on('end', function() {
+      runner.on(Runner.constants.RUNNER_EVENT_END, function() {
         expect(runner.failures, 'to be', 1);
         expect(test.state, 'to be', 'failed');
         done();
@@ -47,7 +47,7 @@ describe('a test that throws', function() {
       });
       suite.addTest(test);
       runner = new Runner(suite);
-      runner.on('end', function() {
+      runner.on(Runner.constants.RUNNER_EVENT_END, function() {
         expect(runner.failures, 'to be', 1);
         expect(test.state, 'to be', 'failed');
         done();
@@ -63,7 +63,7 @@ describe('a test that throws', function() {
       });
       suite.addTest(test);
       runner = new Runner(suite);
-      runner.on('end', function() {
+      runner.on(Runner.constants.RUNNER_EVENT_END, function() {
         expect(runner.failures, 'to be', 1);
         expect(test.state, 'to be', 'failed');
         done();
@@ -79,7 +79,7 @@ describe('a test that throws', function() {
       });
       suite.addTest(test);
       runner = new Runner(suite);
-      runner.on('end', function() {
+      runner.on(Runner.constants.RUNNER_EVENT_END, function() {
         expect(runner.failures, 'to be', 1);
         expect(test.state, 'to be', 'failed');
         done();
@@ -93,7 +93,7 @@ describe('a test that throws', function() {
       });
       suite.addTest(test);
       runner = new Runner(suite);
-      runner.on('end', function() {
+      runner.on(Runner.constants.RUNNER_EVENT_END, function() {
         expect(runner.failures, 'to be', 1);
         expect(test.state, 'to be', 'failed');
         done();
@@ -111,7 +111,7 @@ describe('a test that throws', function() {
       });
       suite.addTest(test);
       runner = new Runner(suite);
-      runner.on('end', function() {
+      runner.on(Runner.constants.RUNNER_EVENT_END, function() {
         expect(runner.failures, 'to be', 1);
         expect(test.state, 'to be', 'failed');
         done();
@@ -127,7 +127,7 @@ describe('a test that throws', function() {
       });
       suite.addTest(test);
       runner = new Runner(suite);
-      runner.on('end', function() {
+      runner.on(Runner.constants.RUNNER_EVENT_END, function() {
         expect(runner.failures, 'to be', 1);
         expect(test.state, 'to be', 'failed');
         done();
@@ -141,7 +141,7 @@ describe('a test that throws', function() {
       });
       suite.addTest(test);
       runner = new Runner(suite);
-      runner.on('end', function() {
+      runner.on(Runner.constants.RUNNER_EVENT_END, function() {
         expect(runner.failures, 'to be', 1);
         expect(test.state, 'to be', 'failed');
         done();
@@ -157,7 +157,7 @@ describe('a test that throws', function() {
       });
       suite.addTest(test);
       runner = new Runner(suite);
-      runner.on('end', function() {
+      runner.on(Runner.constants.RUNNER_EVENT_END, function() {
         expect(runner.failures, 'to be', 1);
         expect(test.state, 'to be', 'failed');
         done();