Consistent quotes
diff --git a/test/clock_test.dart b/test/clock_test.dart
index 0fc44a1..73cdeb4 100644
--- a/test/clock_test.dart
+++ b/test/clock_test.dart
@@ -1,13 +1,13 @@
 // Copyright 2013 Google Inc. All Rights Reserved.
 //
-// Licensed under the Apache License, Version 2.0 (the "License");
+// Licensed under the Apache License, Version 2.0 (the 'License');
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
+// distributed under the License is distributed on an 'AS IS' BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
@@ -31,14 +31,14 @@
       subject = new Clock.fixed(new DateTime(2013));
     });
 
-    test("should return a non-null value from system clock", () {
+    test('should return a non-null value from system clock', () {
       expect(new Clock().now(), isNotNull);
       expect(SYSTEM_CLOCK.now(), isNotNull);
     });
 
     // This test may be flaky on certain systems. I ran it over 10 million
     // cycles on my machine without any failures, but that's no guarantee.
-    test("should be close enough to system clock", () {
+    test('should be close enough to system clock', () {
       // At 10ms the test doesn't seem to be flaky.
       var epsilon = 10;
       expect(new DateTime.now().difference(
@@ -49,7 +49,7 @@
               lessThan(epsilon));
     });
 
-    test("should return time provided by custom TimeFunction", () {
+    test('should return time provided by custom TimeFunction', () {
       var time = new DateTime(2013);
       var fixedClock = new Clock(() => time);
       expect(fixedClock.now(), new DateTime(2013));
@@ -58,19 +58,19 @@
       expect(fixedClock.now(), new DateTime(2014));
     });
 
-    test("should return fixed time", () {
+    test('should return fixed time', () {
       expect(new Clock.fixed(new DateTime(2013)).now(), new DateTime(2013));
     });
 
-    test("should return time Duration ago", () {
+    test('should return time Duration ago', () {
       expect(subject.agoBy(new Duration(days: 366)), new DateTime(2012));
     });
 
-    test("should return time Duration from now", () {
+    test('should return time Duration from now', () {
       expect(subject.fromNowBy(new Duration(days: 365)), new DateTime(2014));
     });
 
-    test("should return time parts ago", () {
+    test('should return time parts ago', () {
       expect(subject.ago(
           days: 1,
           hours: 1,
@@ -80,7 +80,7 @@
           microseconds: 1000), new DateTime(2012, 12, 30, 22, 58, 58, 998));
     });
 
-    test("should return time parts from now", () {
+    test('should return time parts from now', () {
       expect(subject.fromNow(
           days: 1,
           hours: 1,
@@ -90,119 +90,119 @@
           microseconds: 1000), new DateTime(2013, 1, 2, 1, 1, 1, 2));
     });
 
-    test("should return time micros ago", () {
+    test('should return time micros ago', () {
       expect(subject.microsAgo(1000),
           new DateTime(2012, 12, 31, 23, 59, 59, 999));
     });
 
-    test("should return time micros from now", () {
+    test('should return time micros from now', () {
       expect(subject.microsFromNow(1000),
           new DateTime(2013, 1, 1, 0, 0, 0, 1));
     });
 
-    test("should return time millis ago", () {
+    test('should return time millis ago', () {
       expect(subject.millisAgo(1000),
           new DateTime(2012, 12, 31, 23, 59, 59, 000));
     });
 
-    test("should return time millis from now", () {
+    test('should return time millis from now', () {
       expect(subject.millisFromNow(3),
           new DateTime(2013, 1, 1, 0, 0, 0, 3));
     });
 
-    test("should return time seconds ago", () {
+    test('should return time seconds ago', () {
       expect(subject.secondsAgo(10),
           new DateTime(2012, 12, 31, 23, 59, 50, 000));
     });
 
-    test("should return time seconds from now", () {
+    test('should return time seconds from now', () {
       expect(subject.secondsFromNow(3),
           new DateTime(2013, 1, 1, 0, 0, 3, 0));
     });
 
-    test("should return time minutes ago", () {
+    test('should return time minutes ago', () {
       expect(subject.minutesAgo(10),
           new DateTime(2012, 12, 31, 23, 50, 0, 000));
     });
 
-    test("should return time minutes from now", () {
+    test('should return time minutes from now', () {
       expect(subject.minutesFromNow(3),
           new DateTime(2013, 1, 1, 0, 3, 0, 0));
     });
 
-    test("should return time hours ago", () {
+    test('should return time hours ago', () {
       expect(subject.hoursAgo(10),
           new DateTime(2012, 12, 31, 14, 0, 0, 000));
     });
 
-    test("should return time hours from now", () {
+    test('should return time hours from now', () {
       expect(subject.hoursFromNow(3),
           new DateTime(2013, 1, 1, 3, 0, 0, 0));
     });
 
-    test("should return time days ago", () {
+    test('should return time days ago', () {
       expectDate(subject.daysAgo(10), 2012, 12, 22);
     });
 
-    test("should return time days from now", () {
+    test('should return time days from now', () {
       expectDate(subject.daysFromNow(3), 2013, 1, 4);
     });
 
-    test("should return time months ago on the same date", () {
+    test('should return time months ago on the same date', () {
       expectDate(subject.monthsAgo(1), 2012, 12, 1);
       expectDate(subject.monthsAgo(2), 2012, 11, 1);
       expectDate(subject.monthsAgo(3), 2012, 10, 1);
       expectDate(subject.monthsAgo(4), 2012, 9, 1);
     });
 
-    test("should return time months from now on the same date", () {
+    test('should return time months from now on the same date', () {
       expectDate(subject.monthsFromNow(1), 2013, 2, 1);
       expectDate(subject.monthsFromNow(2), 2013, 3, 1);
       expectDate(subject.monthsFromNow(3), 2013, 4, 1);
       expectDate(subject.monthsFromNow(4), 2013, 5, 1);
     });
 
-    test("should go from 2013-05-31 to 2012-11-30", () {
+    test('should go from 2013-05-31 to 2012-11-30', () {
       expectDate(from(2013, 5, 31).monthsAgo(6), 2012, 11, 30);
     });
 
-    test("should go from 2013-03-31 to 2013-02-28 (common year)", () {
+    test('should go from 2013-03-31 to 2013-02-28 (common year)', () {
       expectDate(from(2013, 3, 31).monthsAgo(1), 2013, 2, 28);
     });
 
-    test("should go from 2013-05-31 to 2013-02-28 (common year)", () {
+    test('should go from 2013-05-31 to 2013-02-28 (common year)', () {
       expectDate(from(2013, 5, 31).monthsAgo(3), 2013, 2, 28);
     });
 
-    test("should go from 2004-03-31 to 2004-02-29 (leap year)", () {
+    test('should go from 2004-03-31 to 2004-02-29 (leap year)', () {
       expectDate(from(2004, 3, 31).monthsAgo(1), 2004, 2, 29);
     });
 
-    test("should go from 2013-03-31 to 2013-06-30", () {
+    test('should go from 2013-03-31 to 2013-06-30', () {
       expectDate(from(2013, 3, 31).monthsFromNow(3), 2013, 6, 30);
     });
 
-    test("should go from 2003-12-31 to 2004-02-29 (common to leap)", () {
+    test('should go from 2003-12-31 to 2004-02-29 (common to leap)', () {
       expectDate(from(2003, 12, 31).monthsFromNow(2), 2004, 2, 29);
     });
 
-    test("should go from 2004-02-29 to 2003-02-28 by year", () {
+    test('should go from 2004-02-29 to 2003-02-28 by year', () {
       expectDate(from(2004, 2, 29).yearsAgo(1), 2003, 2, 28);
     });
 
-    test("should go from 2004-02-29 to 2003-02-28 by month", () {
+    test('should go from 2004-02-29 to 2003-02-28 by month', () {
       expectDate(from(2004, 2, 29).monthsAgo(12), 2003, 2, 28);
     });
 
-    test("should go from 2004-02-29 to 2005-02-28 by year", () {
+    test('should go from 2004-02-29 to 2005-02-28 by year', () {
       expectDate(from(2004, 2, 29).yearsFromNow(1), 2005, 2, 28);
     });
 
-    test("should go from 2004-02-29 to 2005-02-28 by month", () {
+    test('should go from 2004-02-29 to 2005-02-28 by month', () {
       expectDate(from(2004, 2, 29).monthsFromNow(12), 2005, 2, 28);
     });
 
-    test("should return time years ago on the same date", () {
+    test('should return time years ago on the same date', () {
       expectDate(subject.yearsAgo(1), 2012, 1, 1);  // leap year
       expectDate(subject.yearsAgo(2), 2011, 1, 1);
       expectDate(subject.yearsAgo(3), 2010, 1, 1);
@@ -213,7 +213,7 @@
       expectDate(subject.yearsAgo(2013), 0, 1, 1);
     });
 
-    test("should return time years from now on the same date", () {
+    test('should return time years from now on the same date', () {
       expectDate(subject.yearsFromNow(1), 2014, 1, 1);
       expectDate(subject.yearsFromNow(2), 2015, 1, 1);
       expectDate(subject.yearsFromNow(3), 2016, 1, 1);