diff --git a/.gitignore b/.gitignore
index b787c0d179..3a84892c54 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,4 +15,9 @@ coverage/
 yarn.lock
 package-lock.json
 mocha.js
+# artifacts from various diff tools
+*_BACKUP_*
+*_BASE_*
+*_LOCAL_*
+*_REMOTE_*
 docs/_site
diff --git a/lib/ms.js b/lib/ms.js
index 9590856052..2fdcaf3242 100644
--- a/lib/ms.js
+++ b/lib/ms.js
@@ -13,22 +13,15 @@ var y = d * 365.25;
 /**
  * Parse or format the given `val`.
  *
- * Options:
- *
- *  - `long` verbose formatting [false]
- *
  * @api public
  * @param {string|number} val
- * @param {Object} options
  * @return {string|number}
  */
-module.exports = function (val, options) {
-  options = options || {};
+module.exports = function (val) {
   if (typeof val === 'string') {
     return parse(val);
   }
-  // https://github.com/mochajs/mocha/pull/1035
-  return options['long'] ? longFormat(val) : shortFormat(val);
+  return format(val);
 };
 
 /**
@@ -74,13 +67,13 @@ function parse (str) {
 }
 
 /**
- * Short format for `ms`.
+ * Format for `ms`.
  *
  * @api private
  * @param {number} ms
  * @return {string}
  */
-function shortFormat (ms) {
+function format (ms) {
   if (ms >= d) {
     return Math.round(ms / d) + 'd';
   }
@@ -95,36 +88,3 @@ function shortFormat (ms) {
   }
   return ms + 'ms';
 }
-
-/**
- * Long format for `ms`.
- *
- * @api private
- * @param {number} ms
- * @return {string}
- */
-function longFormat (ms) {
-  return plural(ms, d, 'day') ||
-    plural(ms, h, 'hour') ||
-    plural(ms, m, 'minute') ||
-    plural(ms, s, 'second') ||
-    ms + ' ms';
-}
-
-/**
- * Pluralization helper.
- *
- * @api private
- * @param {number} ms
- * @param {number} n
- * @param {string} name
- */
-function plural (ms, n, name) {
-  if (ms < n) {
-    return;
-  }
-  if (ms < n * 1.5) {
-    return Math.floor(ms / n) + ' ' + name;
-  }
-  return Math.ceil(ms / n) + ' ' + name + 's';
-}
diff --git a/lib/reporters/base.js b/lib/reporters/base.js
index 8b68a3d51d..0ebc5e7db3 100644
--- a/lib/reporters/base.js
+++ b/lib/reporters/base.js
@@ -155,6 +155,17 @@ exports.cursor = {
   }
 };
 
+function showDiff (err) {
+  return err && err.showDiff !== false && sameType(err.actual, err.expected) && err.expected !== undefined;
+}
+
+function stringifyDiffObjs (err) {
+  if (!utils.isString(err.actual) || !utils.isString(err.expected)) {
+    err.actual = utils.stringify(err.actual);
+    err.expected = utils.stringify(err.expected);
+  }
+}
+
 /**
  * Output the given `failures` as a list.
  *
@@ -183,8 +194,6 @@ exports.list = function (failures) {
     }
     var stack = err.stack || message;
     var index = message ? stack.indexOf(message) : -1;
-    var actual = err.actual;
-    var expected = err.expected;
 
     if (index === -1) {
       msg = message;
@@ -200,12 +209,8 @@ exports.list = function (failures) {
       msg = 'Uncaught ' + msg;
     }
     // explicitly show diff
-    if (err.showDiff !== false && sameType(actual, expected) && expected !== undefined) {
-      if (!(utils.isString(actual) && utils.isString(expected))) {
-        err.actual = actual = utils.stringify(actual);
-        err.expected = expected = utils.stringify(expected);
-      }
-
+    if (showDiff(err)) {
+      stringifyDiffObjs(err);
       fmt = color('error title', '  %s) %s:\n%s') + color('error stack', '\n%s\n');
       var match = message.match(/^([^:]+): expected/);
       msg = '\n      ' + color('error message', match ? match[1] : msg);
@@ -290,6 +295,9 @@ function Base (runner) {
   runner.on('fail', function (test, err) {
     stats.failures = stats.failures || 0;
     stats.failures++;
+    if (showDiff(err)) {
+      stringifyDiffObjs(err);
+    }
     test.err = err;
     failures.push(test);
   });
diff --git a/test/integration/options.spec.js b/test/integration/options.spec.js
index f77da38bb8..e4ecc96cd6 100644
--- a/test/integration/options.spec.js
+++ b/test/integration/options.spec.js
@@ -274,63 +274,28 @@ describe('options', function () {
       });
     });
 
-    it('fails if there are tests marked skip', function (done) {
-      run('options/forbid-pending/skip.js', args, function (err, res) {
-        if (err) {
-          done(err);
-          return;
-        }
-        assert.equal(res.code, 1);
-        assert.equal(res.failures[0].err.message, pendingErrorMessage);
-        done();
-      });
-    });
-
-    it('fails if there are pending tests', function (done) {
-      run('options/forbid-pending/pending.js', args, function (err, res) {
-        if (err) {
-          done(err);
-          return;
-        }
-        assert.equal(res.code, 1);
-        assert.equal(res.failures[0].err.message, pendingErrorMessage);
-        done();
-      });
-    });
-
-    it('fails if tests call `skip()`', function (done) {
-      run('options/forbid-pending/this.skip.js', args, function (err, res) {
-        assert(!err);
-        assert.equal(res.code, 1);
-        assert.equal(res.failures[0].err.message, pendingErrorMessage);
-        done();
-      });
-    });
-
-    it('fails if beforeEach calls `skip()`', function (done) {
-      run('options/forbid-pending/beforeEach-this.skip.js', args, function (err, res) {
-        assert(!err);
-        assert.equal(res.code, 1);
-        assert.equal(res.failures[0].err.message, pendingErrorMessage);
-        done();
-      });
-    });
-
-    it('fails if before calls `skip()`', function (done) {
-      run('options/forbid-pending/before-this.skip.js', args, function (err, res) {
-        assert(!err);
-        assert.equal(res.code, 1);
-        assert.equal(res.failures[0].err.message, pendingErrorMessage);
-        done();
-      });
-    });
+    var forbidPendingFailureTests = {
+      'fails if there are tests marked skip': 'skip.js',
+      'fails if there are pending tests': 'pending.js',
+      'fails if tests call `skip()`': 'this.skip.js',
+      'fails if beforeEach calls `skip()`': 'beforeEach-this.skip.js',
+      'fails if before calls `skip()`': 'before-this.skip.js',
+      'fails if there are tests in suites marked skip': 'skip-suite.js'
+    };
 
-    it('fails if there are tests in suites marked skip', function (done) {
-      run('options/forbid-pending/skip-suite.js', args, function (err, res) {
-        assert(!err);
-        assert.equal(res.code, 1);
-        assert.equal(res.failures[0].err.message, pendingErrorMessage);
-        done();
+    Object.keys(forbidPendingFailureTests).forEach(function (title) {
+      it(title, function (done) {
+        run(path.join('options', 'forbid-pending', forbidPendingFailureTests[title]),
+          args,
+          function (err, res) {
+            if (err) {
+              done(err);
+              return;
+            }
+            assert.equal(res.code, 1);
+            assert.equal(res.failures[0].err.message, pendingErrorMessage);
+            done();
+          });
       });
     });
   });
@@ -344,7 +309,8 @@ describe('options', function () {
     /**
      * Returns a test that executes Mocha in a subprocess with either
      * `--exit`, `--no-exit`, or default behavior.
-     * @param {boolean} shouldExit - Expected result; `true` if Mocha should have force-killed the process.
+     * @param {boolean} shouldExit - Expected result; `true` if Mocha should
+     *   have force-killed the process.
      * @param {string} [behavior] - 'enabled' or 'disabled'
      * @returns {Function}
      */
@@ -392,7 +358,9 @@ describe('options', function () {
   describe('--help', function () {
     it('works despite the presence of mocha.opts', function (done) {
       directInvoke(['-h'], function (error, result) {
-        if (error) { return done(error); }
+        if (error) {
+          return done(error);
+        }
         expect(result.output).to.contain('Usage:');
         done();
       }, path.join(__dirname, 'fixtures', 'options', 'help'));
diff --git a/test/reporters/list.spec.js b/test/reporters/list.spec.js
index 4b3704204d..87978de011 100644
--- a/test/reporters/list.spec.js
+++ b/test/reporters/list.spec.js
@@ -192,6 +192,28 @@ describe('List reporter', function () {
 
       Base.cursor = cachedCursor;
     });
+    it('should immediately construct fail strings', function () {
+      var actual = { a: 'actual' };
+      var expected = { a: 'expected' };
+      var test = {};
+      var checked = false;
+      var err;
+      runner.on = function (event, callback) {
+        if (!checked && event === 'fail') {
+          err = new Error('fake failure object with actual/expected');
+          err.actual = actual;
+          err.expected = expected;
+          err.showDiff = true;
+          callback(test, err);
+          checked = true;
+        }
+      };
+      List.call({epilogue: function () {}}, runner);
+
+      process.stdout.write = stdoutWrite;
+      expect(typeof err.actual).to.equal('string');
+      expect(typeof err.expected).to.equal('string');
+    });
   });
 
   describe('on end', function () {
diff --git a/test/unit/ms.spec.js b/test/unit/ms.spec.js
index e7b1d358be..0844391258 100644
--- a/test/unit/ms.spec.js
+++ b/test/unit/ms.spec.js
@@ -21,45 +21,24 @@ describe('.ms()', function () {
     it('should return short format', function () {
       expect(ms(2000)).to.equal('2s');
     });
-
-    it('should return long format', function () {
-      expect(ms(2000, { long: true })).to.equal('2 seconds');
-      expect(ms(1000, { long: true })).to.equal('1 second');
-      expect(ms(1010, { long: true })).to.equal('1 second');
-    });
   });
 
   describe('minutes representation', function () {
     it('should return short format', function () {
       expect(ms(time.minutes(1))).to.equal('1m');
     });
-
-    it('should return long format', function () {
-      expect(ms(time.minutes(1), { long: true })).to.equal('1 minute');
-      expect(ms(time.minutes(3), { long: true })).to.equal('3 minutes');
-    });
   });
 
   describe('hours representation', function () {
     it('should return short format', function () {
       expect(ms(time.hours(1))).to.equal('1h');
     });
-
-    it('should return long format', function () {
-      expect(ms(time.hours(1), { long: true })).to.equal('1 hour');
-      expect(ms(time.hours(3), { long: true })).to.equal('3 hours');
-    });
   });
 
   describe('days representation', function () {
     it('should return short format', function () {
       expect(ms(time.days(1))).to.equal('1d');
     });
-
-    it('should return long format', function () {
-      expect(ms(time.days(1), { long: true })).to.equal('1 day');
-      expect(ms(time.days(3), { long: true })).to.equal('3 days');
-    });
   });
 
   describe('Getting string value', function () {