Add microsecond support to DateTime.

tests/corelib/date_time_test.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import "package:expect/expect.dart";
 
 // Dart test program for DateTime.
 
+bool get supportsMicroseconds =>
+    new DateTime.fromMicrosecondsSinceEpoch(1).microsecondsSinceEpoch == 1;
+
 // Identical to _MAX_MILLISECONDS_SINCE_EPOCH in date_time.dart
 const int _MAX_MILLISECONDS = 8640000000000000;
 
 // Tests if the time moves eventually forward.
 void testNow() {
   var t1 = new DateTime.now();
   bool timeMovedForward = false;
   const int N = 1000000;
   outer: while (true) {
     for (int i = N; i > 0; i--) {
       var t2 = new DateTime.now();
       if (t1.millisecondsSinceEpoch < t2.millisecondsSinceEpoch) {
         break outer;
       }
     }
     print("testNow: No Date.now() progress in $N loops. Time: $t1");
   }
   Expect.isFalse(t1.isUtc);
 }
 
-void testValue() {
+void testMillisecondsSinceEpoch() {
   var dt1 = new DateTime.now();
   var millisecondsSinceEpoch = dt1.millisecondsSinceEpoch;
   var dt2 = new DateTime.fromMillisecondsSinceEpoch(millisecondsSinceEpoch);
   Expect.equals(millisecondsSinceEpoch, dt2.millisecondsSinceEpoch);
 }
 
+void testMicrosecondsSinceEpoch() {
+  var dt1 = new DateTime.fromMillisecondsSinceEpoch(1);
+  var microsecondsSinceEpoch = dt1.millisecondsSinceEpoch;
+  var dt2 = new DateTime.fromMicrosecondsSinceEpoch(microsecondsSinceEpoch);
+  Expect.equals(microsecondsSinceEpoch, dt2.microsecondsSinceEpoch);
+
+  if (!supportsMicroseconds) return;
+  dt1 = new DateTime.now();
+  microsecondsSinceEpoch = dt1.millisecondsSinceEpoch;
+  dt2 = new DateTime.fromMicrosecondsSinceEpoch(microsecondsSinceEpoch);
+  Expect.equals(microsecondsSinceEpoch, dt2.microsecondsSinceEpoch);
+}
+
 void testFarAwayDates() {
   DateTime dt =
       new DateTime.fromMillisecondsSinceEpoch(1000000000000001, isUtc: true);
   Expect.equals(33658, dt.year);
   Expect.equals(9, dt.month);
   Expect.equals(27, dt.day);
   Expect.equals(1, dt.hour);
   Expect.equals(46, dt.minute);
   Expect.equals(40, dt.second);
   Expect.equals(1, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
   dt = new DateTime.fromMillisecondsSinceEpoch(-1000000000000001, isUtc: true);
   Expect.equals(-29719, dt.year);
   Expect.equals(4, dt.month);
   Expect.equals(5, dt.day);
   Expect.equals(22, dt.hour);
   Expect.equals(13, dt.minute);
   Expect.equals(19, dt.second);
   Expect.equals(999, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
   // Same with local zone.
   dt = new DateTime.fromMillisecondsSinceEpoch(1000000000000001);
   Expect.equals(33658, dt.year);
   Expect.equals(9, dt.month);
   Expect.equals(true, dt.day == 27 || dt.day == 26);
   // Not much we can test for local hour.
   Expect.equals(true, dt.hour >= 0 && dt.hour < 24);
   // Timezones can have offsets down to 15 minute.
   Expect.equals(true, dt.minute % 15 == 46 % 15);
   Expect.equals(40, dt.second);
   Expect.equals(1, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
   dt = new DateTime.fromMillisecondsSinceEpoch(-1000000000000001);
   Expect.equals(-29719, dt.year);
   Expect.equals(4, dt.month);
   Expect.equals(true, 5 == dt.day || 6 == dt.day);
   // Not much we can test for local hour.
   Expect.equals(true, dt.hour >= 0 && dt.hour < 24);
   // Timezones can have offsets down to 15 minute.
   Expect.equals(true, dt.minute % 15 == 13);
   Expect.equals(19, dt.second);
   Expect.equals(999, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
+
+  if (!supportsMicroseconds) return;
+  dt =
+      new DateTime.fromMicrosecondsSinceEpoch(1000000000000000001, isUtc: true);
+  Expect.equals(33658, dt.year);
+  Expect.equals(9, dt.month);
+  Expect.equals(27, dt.day);
+  Expect.equals(1, dt.hour);
+  Expect.equals(46, dt.minute);
+  Expect.equals(40, dt.second);
+  Expect.equals(0, dt.millisecond);
+  Expect.equals(1, dt.microsecond);
+  dt = new DateTime.fromMicrosecondsSinceEpoch(
+      -1000000000000000001, isUtc: true);
+  Expect.equals(-29719, dt.year);
+  Expect.equals(4, dt.month);
+  Expect.equals(5, dt.day);
+  Expect.equals(22, dt.hour);
+  Expect.equals(13, dt.minute);
+  Expect.equals(19, dt.second);
+  Expect.equals(999, dt.millisecond);
+  Expect.equals(999, dt.microsecond);
+  // Same with local zone.
+  dt = new DateTime.fromMicrosecondsSinceEpoch(1000000000000000001);
+  Expect.equals(33658, dt.year);
+  Expect.equals(9, dt.month);
+  Expect.equals(true, dt.day == 27 || dt.day == 26);
+  // Not much we can test for local hour.
+  Expect.equals(true, dt.hour >= 0 && dt.hour < 24);
+  // Timezones can have offsets down to 15 minute.
+  Expect.equals(true, dt.minute % 15 == 46 % 15);
+  Expect.equals(40, dt.second);
+  Expect.equals(0, dt.millisecond);
+  Expect.equals(1, dt.microsecond);
+  dt = new DateTime.fromMicrosecondsSinceEpoch(-1000000000000000001);
+  Expect.equals(-29719, dt.year);
+  Expect.equals(4, dt.month);
+  Expect.equals(true, 5 == dt.day || 6 == dt.day);
+  // Not much we can test for local hour.
+  Expect.equals(true, dt.hour >= 0 && dt.hour < 24);
+  // Timezones can have offsets down to 15 minute.
+  Expect.equals(true, dt.minute % 15 == 13);
+  Expect.equals(19, dt.second);
+  Expect.equals(999, dt.millisecond);
+  Expect.equals(999, dt.microsecond);
 }
 
 void testEquivalentYears() {
   // All hardcoded values come from V8. This means that the values are not
   // necessarily correct (see limitations of DateTime object in
   // EcmaScript 15.9.1 and in particular 15.9.1.8/9).
   DateTime dt = new DateTime.fromMillisecondsSinceEpoch(-31485600000, isUtc: true);
   Expect.equals(1969, dt.year);
   Expect.equals(1, dt.month);
   Expect.equals(1, dt.day);
   Expect.equals(14, dt.hour);
   Expect.equals(0, dt.minute);
   Expect.equals(0, dt.second);
   Expect.equals(0, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
   dt = new DateTime.fromMillisecondsSinceEpoch(-63108000000, isUtc: true);
   Expect.equals(1968, dt.year);
   Expect.equals(1, dt.month);
   Expect.equals(1, dt.day);
   Expect.equals(14, dt.hour);
   Expect.equals(0, dt.minute);
   Expect.equals(0, dt.second);
   Expect.equals(0, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
   dt = new DateTime.fromMillisecondsSinceEpoch(-94644000000, isUtc: true);
   Expect.equals(1967, dt.year);
   Expect.equals(1, dt.month);
   Expect.equals(1, dt.day);
   Expect.equals(14, dt.hour);
   Expect.equals(0, dt.minute);
   Expect.equals(0, dt.second);
   Expect.equals(0, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
   dt = new DateTime.fromMillisecondsSinceEpoch(-126180000000, isUtc: true);
   Expect.equals(1966, dt.year);
   Expect.equals(1, dt.month);
   Expect.equals(1, dt.day);
   Expect.equals(14, dt.hour);
   Expect.equals(0, dt.minute);
   Expect.equals(0, dt.second);
   Expect.equals(0, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
   dt = new DateTime.fromMillisecondsSinceEpoch(-157716000000, isUtc: true);
   Expect.equals(1965, dt.year);
   Expect.equals(1, dt.month);
   Expect.equals(1, dt.day);
   Expect.equals(14, dt.hour);
   Expect.equals(0, dt.minute);
   Expect.equals(0, dt.second);
   Expect.equals(0, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
   dt = new DateTime.fromMillisecondsSinceEpoch(-2177402400000, isUtc: true);
   Expect.equals(1901, dt.year);
   Expect.equals(1, dt.month);
   Expect.equals(1, dt.day);
   Expect.equals(14, dt.hour);
   Expect.equals(0, dt.minute);
   Expect.equals(0, dt.second);
   Expect.equals(0, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
   dt = new DateTime.fromMillisecondsSinceEpoch(-5333076000000, isUtc: true);
   Expect.equals(1801, dt.year);
   Expect.equals(1, dt.month);
   Expect.equals(1, dt.day);
   Expect.equals(14, dt.hour);
   Expect.equals(0, dt.minute);
   Expect.equals(0, dt.second);
   Expect.equals(0, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
   dt = new DateTime.fromMillisecondsSinceEpoch(-8520285600000, isUtc: true);
   Expect.equals(1700, dt.year);
   Expect.equals(1, dt.month);
   Expect.equals(1, dt.day);
   Expect.equals(14, dt.hour);
   Expect.equals(0, dt.minute);
   Expect.equals(0, dt.second);
   Expect.equals(0, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
   dt = new DateTime.fromMillisecondsSinceEpoch(-14831719200000, isUtc: true);
   Expect.equals(1500, dt.year);
   Expect.equals(1, dt.month);
   Expect.equals(1, dt.day);
   Expect.equals(14, dt.hour);
   Expect.equals(0, dt.minute);
   Expect.equals(0, dt.second);
   Expect.equals(0, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
   dt = new DateTime.fromMillisecondsSinceEpoch(-59011408800000, isUtc: true);
   Expect.equals(100, dt.year);
   Expect.equals(1, dt.month);
   Expect.equals(1, dt.day);
   Expect.equals(14, dt.hour);
   Expect.equals(0, dt.minute);
   Expect.equals(0, dt.second);
   Expect.equals(0, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
   dt = new DateTime.fromMillisecondsSinceEpoch(-62011408800000, isUtc: true);
   Expect.equals(4, dt.year);
   Expect.equals(12, dt.month);
   Expect.equals(8, dt.day);
   Expect.equals(8, dt.hour);
   Expect.equals(40, dt.minute);
   Expect.equals(0, dt.second);
   Expect.equals(0, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
   dt = new DateTime.fromMillisecondsSinceEpoch(-64011408800000, isUtc: true);
   Expect.equals(-59, dt.year);
   Expect.equals(7, dt.month);
   Expect.equals(24, dt.day);
   Expect.equals(5, dt.hour);
   Expect.equals(6, dt.minute);
   Expect.equals(40, dt.second);
   Expect.equals(0, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
   final int SECONDS_YEAR_2035 = 2051222400;
   dt = new DateTime.fromMillisecondsSinceEpoch(SECONDS_YEAR_2035 * 1000 + 1,
                                            isUtc: true);
   Expect.equals(2035, dt.year);
   Expect.equals(1, dt.month);
   Expect.equals(1, dt.day);
   Expect.equals(0, dt.hour);
   Expect.equals(0, dt.minute);
   Expect.equals(0, dt.second);
   Expect.equals(1, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
   dt = new DateTime.fromMillisecondsSinceEpoch(SECONDS_YEAR_2035 * 1000 - 1,
                                            isUtc: true);
   Expect.equals(2034, dt.year);
   Expect.equals(12, dt.month);
   Expect.equals(31, dt.day);
   Expect.equals(23, dt.hour);
   Expect.equals(59, dt.minute);
   Expect.equals(59, dt.second);
   Expect.equals(999, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
+
   dt = new DateTime.utc(2035, 1, 1, 0, 0, 0, 1);
   Expect.equals(SECONDS_YEAR_2035 * 1000 + 1, dt.millisecondsSinceEpoch);
   dt = new DateTime.utc(2034, 12, 31, 23, 59, 59, 999);
   Expect.equals(SECONDS_YEAR_2035 * 1000 - 1, dt.millisecondsSinceEpoch);
   dt = new DateTime.fromMillisecondsSinceEpoch(SECONDS_YEAR_2035 * 1000 + 1);
   Expect.equals(true, (2035 == dt.year && 1 == dt.month && 1 == dt.day) ||
                       (2034 == dt.year && 12 == dt.month && 31 == dt.day));
   Expect.equals(0, dt.second);
   Expect.equals(1, dt.millisecond);
   DateTime dt2 = new DateTime(
       dt.year, dt.month, dt.day, dt.hour, dt.minute, dt.second,
       dt.millisecond);
   Expect.equals(dt.millisecondsSinceEpoch, dt2.millisecondsSinceEpoch);
   dt = new DateTime.fromMillisecondsSinceEpoch(SECONDS_YEAR_2035 * 1000 - 1);
   Expect.equals(true, (2035 == dt.year && 1 == dt.month && 1 == dt.day) ||
                       (2034 == dt.year && 12 == dt.month && 31 == dt.day));
   Expect.equals(59, dt.second);
   Expect.equals(999, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
+
   dt2 = new DateTime(
       dt.year, dt.month, dt.day, dt.hour, dt.minute, dt.second,
       dt.millisecond);
   Expect.equals(dt.millisecondsSinceEpoch, dt2.millisecondsSinceEpoch);
   dt = new DateTime.fromMillisecondsSinceEpoch(2100000000 * 1000, isUtc: true);
   Expect.equals(2036, dt.year);
   Expect.equals(7, dt.month);
   Expect.equals(18, dt.day);
   Expect.equals(13, dt.hour);
   Expect.equals(20, dt.minute);
   Expect.equals(0, dt.second);
   Expect.equals(0, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
+
   // Internally this will use the maximum value for the native calls.
   dt = new DateTime(2036, 7, 18, 13, 20);
   Expect.equals(2036, dt.year);
   Expect.equals(7, dt.month);
   Expect.equals(18, dt.day);
   Expect.equals(13, dt.hour);
   Expect.equals(20, dt.minute);
   Expect.equals(0, dt.second);
   Expect.equals(0, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
   Expect.equals("2036-07-18 13:20:00.000", dt.toString());
+
+  if (!supportsMicroseconds) return;
+
+  dt = new DateTime.utc(2035, 1, 1, 0, 0, 0, 0, 1);
+  Expect.equals(SECONDS_YEAR_2035 * 1000000 + 1, dt.microsecondsSinceEpoch);
+  dt = new DateTime.utc(2034, 12, 31, 23, 59, 59, 999, 999);
+  Expect.equals(SECONDS_YEAR_2035 * 1000000 - 1, dt.microsecondsSinceEpoch);
+  dt = new DateTime.fromMicrosecondsSinceEpoch(SECONDS_YEAR_2035 * 1000000 + 1);
+  Expect.equals(true, (2035 == dt.year && 1 == dt.month && 1 == dt.day) ||
+                      (2034 == dt.year && 12 == dt.month && 31 == dt.day));
+  Expect.equals(0, dt.second);
+  Expect.equals(0, dt.millisecond);
+  Expect.equals(1, dt.microsecond);
+  dt2 = new DateTime(
+      dt.year, dt.month, dt.day, dt.hour, dt.minute, dt.second,
+      dt.millisecond, dt.microsecond);
+  Expect.equals(dt.microsecondsSinceEpoch, dt2.microsecondsSinceEpoch);
+  dt = new DateTime.fromMicrosecondsSinceEpoch(SECONDS_YEAR_2035 * 1000000 - 1);
+  Expect.equals(true, (2035 == dt.year && 1 == dt.month && 1 == dt.day) ||
+                      (2034 == dt.year && 12 == dt.month && 31 == dt.day));
+  Expect.equals(59, dt.second);
+  Expect.equals(999, dt.millisecond);
+  Expect.equals(999, dt.microsecond);
+
+  dt2 = new DateTime(
+      dt.year, dt.month, dt.day, dt.hour, dt.minute, dt.second,
+      dt.millisecond, dt.microsecond);
+  Expect.equals(dt.millisecondsSinceEpoch, dt2.millisecondsSinceEpoch);
+  dt = new DateTime.fromMicrosecondsSinceEpoch(2100000000 * 1000000,
+      isUtc: true);
+  Expect.equals(2036, dt.year);
+  Expect.equals(7, dt.month);
+  Expect.equals(18, dt.day);
+  Expect.equals(13, dt.hour);
+  Expect.equals(20, dt.minute);
+  Expect.equals(0, dt.second);
+  Expect.equals(0, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
 }
 
 void testExtremes() {
   var dt =
       new DateTime.fromMillisecondsSinceEpoch(_MAX_MILLISECONDS, isUtc: true);
   Expect.equals(275760, dt.year);
   Expect.equals(9, dt.month);
   Expect.equals(13, dt.day);
   Expect.equals(0, dt.hour);
   Expect.equals(0, dt.minute);
   Expect.equals(0, dt.second);
   Expect.equals(0, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
   dt = new DateTime.fromMillisecondsSinceEpoch(-_MAX_MILLISECONDS, isUtc: true);
   Expect.equals(-271821, dt.year);
   Expect.equals(4, dt.month);
   Expect.equals(20, dt.day);
   Expect.equals(0, dt.hour);
   Expect.equals(0, dt.minute);
   Expect.equals(0, dt.second);
   Expect.equals(0, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
   // Make sure that we can build the extreme dates in local too.
   dt = new DateTime.fromMillisecondsSinceEpoch(_MAX_MILLISECONDS);
   dt = new DateTime(dt.year, dt.month, dt.day, dt.hour, dt.minute);
   Expect.equals(_MAX_MILLISECONDS, dt.millisecondsSinceEpoch);
   dt = new DateTime.fromMillisecondsSinceEpoch(-_MAX_MILLISECONDS);
   dt = new DateTime(dt.year, dt.month, dt.day, dt.hour, dt.minute);
   Expect.equals(-_MAX_MILLISECONDS, dt.millisecondsSinceEpoch);
   Expect.throws(() => new DateTime.fromMillisecondsSinceEpoch(
       _MAX_MILLISECONDS + 1, isUtc: true));
   Expect.throws(() => new DateTime.fromMillisecondsSinceEpoch(
       -_MAX_MILLISECONDS - 1, isUtc: true));
   Expect.throws(() => new DateTime.fromMillisecondsSinceEpoch(
       _MAX_MILLISECONDS + 1));
   Expect.throws(() => new DateTime.fromMillisecondsSinceEpoch(
       -_MAX_MILLISECONDS - 1));
   dt = new DateTime.fromMillisecondsSinceEpoch(_MAX_MILLISECONDS);
   Expect.throws(() => new DateTime(dt.year, dt.month, dt.day,
                                dt.hour, dt.minute, 0, 1));
   dt = new DateTime.fromMillisecondsSinceEpoch(_MAX_MILLISECONDS, isUtc: true);
   Expect.throws(() => new DateTime.utc(dt.year, dt.month, dt.day,
                                    dt.hour, dt.minute, 0, 1));
   dt = new DateTime.fromMillisecondsSinceEpoch(-_MAX_MILLISECONDS);
   Expect.throws(() => new DateTime(dt.year, dt.month, dt.day,
                                dt.hour, dt.minute, 0, -1));
   dt = new DateTime.fromMillisecondsSinceEpoch(-_MAX_MILLISECONDS, isUtc: true);
   Expect.throws(() => new DateTime.utc(dt.year, dt.month, dt.day,
                                    dt.hour, dt.minute, 0, -1));
+
+  if (!supportsMicroseconds) return;
+
+  dt = new DateTime.fromMicrosecondsSinceEpoch(_MAX_MILLISECONDS * 1000);
+  dt = new DateTime(dt.year, dt.month, dt.day, dt.hour, dt.minute);
+  Expect.equals(_MAX_MILLISECONDS * 1000, dt.microsecondsSinceEpoch);
+  dt = new DateTime.fromMicrosecondsSinceEpoch(-_MAX_MILLISECONDS * 1000);
+  dt = new DateTime(dt.year, dt.month, dt.day, dt.hour, dt.minute);
+  Expect.equals(-_MAX_MILLISECONDS * 1000, dt.microsecondsSinceEpoch);
+  Expect.throws(() => new DateTime.fromMicrosecondsSinceEpoch(
+      _MAX_MILLISECONDS * 1000 + 1, isUtc: true));
+  Expect.throws(() => new DateTime.fromMicrosecondsSinceEpoch(
+      -_MAX_MILLISECONDS * 1000 - 1, isUtc: true));
+  Expect.throws(() => new DateTime.fromMicrosecondsSinceEpoch(
+      _MAX_MILLISECONDS * 1000 + 1));
+  Expect.throws(() => new DateTime.fromMicrosecondsSinceEpoch(
+      -_MAX_MILLISECONDS * 1000 - 1));
+  dt = new DateTime.fromMillisecondsSinceEpoch(_MAX_MILLISECONDS);
+  Expect.throws(() => new DateTime(dt.year, dt.month, dt.day,
+                               dt.hour, dt.minute, 0, 0, 1));
+  dt = new DateTime.fromMillisecondsSinceEpoch(_MAX_MILLISECONDS, isUtc: true);
+  Expect.throws(() => new DateTime.utc(dt.year, dt.month, dt.day,
+                                   dt.hour, dt.minute, 0, 0, 1));
+  dt = new DateTime.fromMillisecondsSinceEpoch(-_MAX_MILLISECONDS);
+  Expect.throws(() => new DateTime(dt.year, dt.month, dt.day,
+                               dt.hour, dt.minute, 0, 0, -1));
+  dt = new DateTime.fromMillisecondsSinceEpoch(-_MAX_MILLISECONDS, isUtc: true);
+  Expect.throws(() => new DateTime.utc(dt.year, dt.month, dt.day,
+                                   dt.hour, dt.minute, 0, 0, -1));
 }
 
 void testUTCGetters() {
   var dt = new DateTime.fromMillisecondsSinceEpoch(1305140315000, isUtc: true);
   Expect.equals(2011, dt.year);
   Expect.equals(5, dt.month);
   Expect.equals(11, dt.day);
   Expect.equals(18, dt.hour);
   Expect.equals(58, dt.minute);
   Expect.equals(35, dt.second);
   Expect.equals(0, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
   Expect.equals(true, dt.isUtc);
   Expect.equals(1305140315000, dt.millisecondsSinceEpoch);
   dt = new DateTime.fromMillisecondsSinceEpoch(-9999999, isUtc: true);
   Expect.equals(1969, dt.year);
   Expect.equals(12, dt.month);
   Expect.equals(31, dt.day);
   Expect.equals(21, dt.hour);
   Expect.equals(13, dt.minute);
   Expect.equals(20, dt.second);
   Expect.equals(1, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
+
+  if (!supportsMicroseconds) return;
+
+  dt = new DateTime.fromMicrosecondsSinceEpoch(-9999999999, isUtc: true);
+  Expect.equals(1969, dt.year);
+  Expect.equals(12, dt.month);
+  Expect.equals(31, dt.day);
+  Expect.equals(21, dt.hour);
+  Expect.equals(13, dt.minute);
+  Expect.equals(20, dt.second);
+  Expect.equals(0, dt.millisecond);
+  Expect.equals(1, dt.microsecond);
 }
 
 void testLocalGetters() {
   var dt1 = new DateTime.fromMillisecondsSinceEpoch(1305140315000);
   var dt2 = new DateTime.utc(dt1.year, dt1.month, dt1.day,
-                         dt1.hour, dt1.minute, dt1.second, dt1.millisecond);
+                         dt1.hour, dt1.minute, dt1.second, dt1.millisecond,
+                         dt1.microsecond);
   Duration zoneOffset = dt1.difference(dt2);
   Expect.equals(true, zoneOffset.inDays == 0);
   Expect.equals(true, zoneOffset.inHours.abs() <= 12);
   Expect.equals(dt1.year, dt2.year);
   Expect.equals(dt1.month, dt2.month);
   Expect.equals(true, (dt1.day - dt2.day).abs() <= 1);
   Expect.equals(true, dt1.hour < 24);
   // There are timezones with 0.5 or 0.25 hour offsets.
   Expect.equals(true,
                 (dt1.minute == dt2.minute) ||
                 ((dt1.minute - dt2.minute).abs() == 30) ||
                 ((dt1.minute - dt2.minute).abs() == 15));
   Expect.equals(dt1.second, dt2.second);
   Expect.equals(dt1.millisecond, dt2.millisecond);
+  Expect.equals(dt1.microsecond, dt2.microsecond);
 }
 
 void testConstructors() {
-  var dt0 = new DateTime.utc(2011, 5, 11, 18, 58, 35, 0);
-  var dt0b = new DateTime.utc(2011, 5, 11, 18, 58, 35, 0).toLocal();
+  var dt0 = new DateTime.utc(2011, 5, 11, 18, 58, 35, 0, 0);
+  var dt0b = new DateTime.utc(2011, 5, 11, 18, 58, 35, 0, 0).toLocal();
   Expect.equals(1305140315000, dt0.millisecondsSinceEpoch);
   var dt1 = new DateTime.fromMillisecondsSinceEpoch(1305140315000);
   Expect.equals(dt1.millisecondsSinceEpoch, dt0.millisecondsSinceEpoch);
+  Expect.equals(dt1.microsecondsSinceEpoch, dt0.microsecondsSinceEpoch);
   Expect.equals(false, dt1 == dt0);
   Expect.equals(true, dt1 == dt0b);
   var dt3 = new DateTime(dt1.year, dt1.month, dt1.day, dt1.hour, dt1.minute,
-                     dt1.second, dt1.millisecond);
+                     dt1.second, dt1.millisecond, dt1.microsecond);
   Expect.equals(dt1.millisecondsSinceEpoch, dt3.millisecondsSinceEpoch);
+  Expect.equals(dt1.microsecondsSinceEpoch, dt3.microsecondsSinceEpoch);
   Expect.equals(false, dt3 == dt0);
   Expect.equals(true, dt1 == dt3);
   dt3 = new DateTime(
       dt1.year, dt1.month, dt1.day, dt1.hour, dt1.minute,
-      dt1.second, dt1.millisecond);
+      dt1.second, dt1.millisecond, dt1.microsecond);
   Expect.equals(dt1.millisecondsSinceEpoch, dt3.millisecondsSinceEpoch);
+  Expect.equals(dt1.microsecondsSinceEpoch, dt3.microsecondsSinceEpoch);
   Expect.equals(true, dt1 == dt3);
   var dt2 = dt1.toLocal();
-  dt3 = new DateTime(2011, 5, dt1.day, dt1.hour, dt1.minute, 35, 0);
+  dt3 = new DateTime(2011, 5, dt1.day, dt1.hour, dt1.minute, 35, 0, 0);
   Expect.equals(dt2.millisecondsSinceEpoch, dt3.millisecondsSinceEpoch);
+  Expect.equals(dt2.microsecondsSinceEpoch, dt3.microsecondsSinceEpoch);
   Expect.equals(true, dt2 == dt3);
   dt1 = new DateTime.fromMillisecondsSinceEpoch(-9999999, isUtc: true);
   dt3 = new DateTime.utc(dt1.year, dt1.month, dt1.day, dt1.hour, dt1.minute,
                      dt1.second, dt1.millisecond);
   Expect.equals(dt1.millisecondsSinceEpoch, dt3.millisecondsSinceEpoch);
+  Expect.equals(dt1.microsecondsSinceEpoch, dt3.microsecondsSinceEpoch);
   dt3 = new DateTime.utc(99, 1, 2, 10, 11, 12, 0);
   Expect.equals(99, dt3.year);
   Expect.equals(1, dt3.month);
   Expect.equals(2, dt3.day);
   Expect.equals(10, dt3.hour);
   Expect.equals(11, dt3.minute);
   Expect.equals(12, dt3.second);
   Expect.equals(0, dt3.millisecond);
+  Expect.equals(0, dt3.microsecond);
   Expect.equals(true, dt3.isUtc);
   var dt4 = new DateTime(99, 1, 2);
   Expect.equals(99, dt4.year);
   Expect.equals(1, dt4.month);
   Expect.equals(2, dt4.day);
   Expect.equals(0, dt4.hour);
   Expect.equals(0, dt4.minute);
   Expect.equals(0, dt4.second);
   Expect.equals(0, dt4.millisecond);
+  Expect.equals(0, dt4.microsecond);
   Expect.isFalse(dt4.isUtc);
   var dt5 = new DateTime.utc(99, 1, 2);
   Expect.equals(99, dt5.year);
   Expect.equals(1, dt5.month);
   Expect.equals(2, dt5.day);
   Expect.equals(0, dt5.hour);
   Expect.equals(0, dt5.minute);
   Expect.equals(0, dt5.second);
   Expect.equals(0, dt5.millisecond);
+  Expect.equals(0, dt5.microsecond);
   Expect.isTrue(dt5.isUtc);
   var dt6 = new DateTime(2012, 2, 27, 13, 27, 0);
   Expect.equals(2012, dt6.year);
   Expect.equals(2, dt6.month);
   Expect.equals(27, dt6.day);
   Expect.equals(13, dt6.hour);
   Expect.equals(27, dt6.minute);
   Expect.equals(0, dt6.second);
   Expect.equals(0, dt6.millisecond);
+  Expect.equals(0, dt6.microsecond);
   Expect.isFalse(dt6.isUtc);
   var dt7 = new DateTime.utc(2012, 2, 27, 13, 27, 0);
   Expect.equals(2012, dt7.year);
   Expect.equals(2, dt7.month);
   Expect.equals(27, dt7.day);
   Expect.equals(13, dt7.hour);
   Expect.equals(27, dt7.minute);
   Expect.equals(0, dt7.second);
   Expect.equals(0, dt7.millisecond);
+  Expect.equals(0, dt7.microsecond);
   Expect.isTrue(dt7.isUtc);
 }
 
 void testChangeTimeZone() {
   var dt1 = new DateTime.fromMillisecondsSinceEpoch(1305140315000);
   var dt2 = dt1.toUtc();
   Expect.equals(dt1.millisecondsSinceEpoch, dt2.millisecondsSinceEpoch);
   var dt3 = new DateTime.fromMillisecondsSinceEpoch(1305140315000, isUtc: true);
   Expect.equals(dt1.millisecondsSinceEpoch, dt3.millisecondsSinceEpoch);
   Expect.equals(dt2.year, dt3.year);
   Expect.equals(dt2.month, dt3.month);
   Expect.equals(dt2.day, dt3.day);
   Expect.equals(dt2.hour, dt3.hour);
   Expect.equals(dt2.minute, dt3.minute);
   Expect.equals(dt2.second, dt3.second);
   Expect.equals(dt2.millisecond, dt3.millisecond);
+  Expect.equals(dt2.microsecond, dt3.microsecond);
   var dt4 = dt3.toLocal();
   Expect.equals(dt1.year, dt4.year);
   Expect.equals(dt1.month, dt4.month);
   Expect.equals(dt1.day, dt4.day);
   Expect.equals(dt1.hour, dt4.hour);
   Expect.equals(dt1.minute, dt4.minute);
   Expect.equals(dt1.second, dt4.second);
   Expect.equals(dt1.millisecond, dt4.millisecond);
+  Expect.equals(dt1.microsecond, dt4.microsecond);
 }
 
 void testSubAdd() {
   var dt1 = new DateTime.fromMillisecondsSinceEpoch(1305140315000, isUtc: true);
   var dt2 = dt1.add(new Duration(milliseconds:
       3 * Duration.MILLISECONDS_PER_SECOND + 5));
   Expect.equals(dt1.year, dt2.year);
   Expect.equals(dt1.month, dt2.month);
   Expect.equals(dt1.day, dt2.day);
   Expect.equals(dt1.hour, dt2.hour);
   Expect.equals(dt1.minute, dt2.minute);
   Expect.equals(dt1.second + 3, dt2.second);
   Expect.equals(dt1.millisecond + 5, dt2.millisecond);
+  Expect.equals(dt1.microsecond, dt2.microsecond);
   var dt3 = dt2.subtract(new Duration(milliseconds:
       3 * Duration.MILLISECONDS_PER_SECOND + 5));
   Expect.equals(true, dt1 == dt3);
   Expect.equals(false, dt1 == dt2);
+
+  if (!supportsMicroseconds) return;
+
+  dt1 = new DateTime.fromMillisecondsSinceEpoch(1305140315000, isUtc: true);
+  dt2 = dt1.add(new Duration(microseconds:
+      3 * Duration.MICROSECONDS_PER_SECOND + 5));
+  Expect.equals(dt1.year, dt2.year);
+  Expect.equals(dt1.month, dt2.month);
+  Expect.equals(dt1.day, dt2.day);
+  Expect.equals(dt1.hour, dt2.hour);
+  Expect.equals(dt1.minute, dt2.minute);
+  Expect.equals(dt1.second + 3, dt2.second);
+  Expect.equals(dt1.millisecond, dt2.millisecond);
+  Expect.equals(dt1.microsecond + 5, dt2.microsecond);
+  dt3 = dt2.subtract(new Duration(microseconds:
+      3 * Duration.MICROSECONDS_PER_SECOND + 5));
+  Expect.equals(true, dt1 == dt3);
+  Expect.equals(false, dt1 == dt2);
 }
 
 void testUnderflowAndOverflow() {
-  final dtBase = new DateTime(2012, 6, 20, 12, 30, 30, 500);
+  int microsecond = supportsMicroseconds ? 499 : 0;
+  final dtBase = new DateTime(2012, 6, 20, 12, 30, 30, 500, microsecond);
 
   // Millisecond
   print("  >>> Millisecond+");
   var dt = new DateTime(dtBase.year, dtBase.month, dtBase.day, dtBase.hour,
-                    dtBase.minute, dtBase.second, 1000);
+                    dtBase.minute, dtBase.second, 1000, dtBase.microsecond);
   Expect.equals(dtBase.year, dt.year);
   Expect.equals(dtBase.month, dt.month);
   Expect.equals(dtBase.day, dt.day);
   Expect.equals(dtBase.hour, dt.hour);
   Expect.equals(dtBase.minute, dt.minute);
   Expect.equals(dtBase.second + 1, dt.second);
   Expect.equals(0, dt.millisecond);
+  Expect.equals(dtBase.microsecond, dt.microsecond);
 
   print("  >>> Millisecond-");
   dt = new DateTime(dtBase.year, dtBase.month, dtBase.day, dtBase.hour,
-                dtBase.minute, dtBase.second, -1000);
+                dtBase.minute, dtBase.second, -1000, dtBase.microsecond);
   Expect.equals(dtBase.year, dt.year);
   Expect.equals(dtBase.month, dt.month);
   Expect.equals(dtBase.day, dt.day);
   Expect.equals(dtBase.hour, dt.hour);
   Expect.equals(dtBase.minute, dt.minute);
   Expect.equals(dtBase.second - 1, dt.second);
   Expect.equals(0, dt.millisecond);
+  Expect.equals(dtBase.microsecond, dt.microsecond);
 
   // Second
   print("  >>> Second+");
   dt = new DateTime(dtBase.year, dtBase.month, dtBase.day, dtBase.hour,
-                dtBase.minute, 60, dtBase.millisecond);
+                dtBase.minute, 60, dtBase.millisecond, dtBase.microsecond);
   Expect.equals(dtBase.year, dt.year);
   Expect.equals(dtBase.month, dt.month);
   Expect.equals(dtBase.day, dt.day);
   Expect.equals(dtBase.hour, dt.hour);
   Expect.equals(dtBase.minute + 1, dt.minute);
   Expect.equals(0, dt.second);
   Expect.equals(dtBase.millisecond, dt.millisecond);
+  Expect.equals(dtBase.microsecond, dt.microsecond);
 
   print("  >>> Second-");
   dt = new DateTime(dtBase.year, dtBase.month, dtBase.day, dtBase.hour,
-                dtBase.minute, -60, dtBase.millisecond);
+                dtBase.minute, -60, dtBase.millisecond, dtBase.microsecond);
   Expect.equals(dtBase.year, dt.year);
   Expect.equals(dtBase.month, dt.month);
   Expect.equals(dtBase.day, dt.day);
   Expect.equals(dtBase.hour, dt.hour);
   Expect.equals(dtBase.minute - 1, dt.minute);
   Expect.equals(0, dt.second);
   Expect.equals(dtBase.millisecond, dt.millisecond);
+  Expect.equals(dtBase.microsecond, dt.microsecond);
 
   // Minute
   print("  >>> Minute+");
   dt = new DateTime(dtBase.year, dtBase.month, dtBase.day, dtBase.hour, 60,
-                dtBase.second, dtBase.millisecond);
+                dtBase.second, dtBase.millisecond, dtBase.microsecond);
   Expect.equals(dtBase.year, dt.year);
   Expect.equals(dtBase.month, dt.month);
   Expect.equals(dtBase.day, dt.day);
   Expect.equals(dtBase.hour + 1, dt.hour);
   Expect.equals(0, dt.minute);
   Expect.equals(dtBase.second, dt.second);
   Expect.equals(dtBase.millisecond, dt.millisecond);
+  Expect.equals(dtBase.microsecond, dt.microsecond);
 
   print("  >>> Minute-");
   dt = new DateTime(dtBase.year, dtBase.month, dtBase.day, dtBase.hour, -60,
-                dtBase.second, dtBase.millisecond);
+                dtBase.second, dtBase.millisecond, dtBase.microsecond);
   Expect.equals(dtBase.year, dt.year);
   Expect.equals(dtBase.month, dt.month);
   Expect.equals(dtBase.day, dt.day);
   Expect.equals(dtBase.hour - 1, dt.hour);
   Expect.equals(0, dt.minute);
   Expect.equals(dtBase.second, dt.second);
   Expect.equals(dtBase.millisecond, dt.millisecond);
+  Expect.equals(dtBase.microsecond, dt.microsecond);
 
   // Hour
   print("  >>> Hour+");
   dt = new DateTime(dtBase.year, dtBase.month, dtBase.day, 24, dtBase.minute,
-                dtBase.second, dtBase.millisecond);
+                dtBase.second, dtBase.millisecond, dtBase.microsecond);
   Expect.equals(dtBase.year, dt.year);
   Expect.equals(dtBase.month, dt.month);
   Expect.equals(dtBase.day + 1, dt.day);
   Expect.equals(0, dt.hour);
   Expect.equals(dtBase.minute, dt.minute);
   Expect.equals(dtBase.second, dt.second);
   Expect.equals(dtBase.millisecond, dt.millisecond);
+  Expect.equals(dtBase.microsecond, dt.microsecond);
 
   print("  >>> Hour-");
   dt = new DateTime(dtBase.year, dtBase.month, dtBase.day, -24, dtBase.minute,
-                dtBase.second, dtBase.millisecond);
+                dtBase.second, dtBase.millisecond, dtBase.microsecond);
   Expect.equals(dtBase.year, dt.year);
   Expect.equals(dtBase.month, dt.month);
   Expect.equals(dtBase.day - 1, dt.day);
   Expect.equals(0, dt.hour);
   Expect.equals(dtBase.minute, dt.minute);
   Expect.equals(dtBase.second, dt.second);
   Expect.equals(dtBase.millisecond, dt.millisecond);
+  Expect.equals(dtBase.microsecond, dt.microsecond);
 
   // Day
   print("  >>> Day+");
   dt = new DateTime(dtBase.year, dtBase.month, 31, dtBase.hour, dtBase.minute,
-                dtBase.second, dtBase.millisecond);
+                dtBase.second, dtBase.millisecond, dtBase.microsecond);
   Expect.equals(dtBase.year, dt.year);
   Expect.equals(dtBase.month + 1, dt.month);
   Expect.equals(1, dt.day);
   Expect.equals(dtBase.hour, dt.hour);
   Expect.equals(dtBase.minute, dt.minute);
   Expect.equals(dtBase.second, dt.second);
   Expect.equals(dtBase.millisecond, dt.millisecond);
+  Expect.equals(dtBase.microsecond, dt.microsecond);
 
   print("  >>> Day-");
   dt = new DateTime(dtBase.year, dtBase.month, -30, dtBase.hour, dtBase.minute,
-                dtBase.second, dtBase.millisecond);
+                dtBase.second, dtBase.millisecond, dtBase.microsecond);
   Expect.equals(dtBase.year, dt.year);
   Expect.equals(dtBase.month - 1, dt.month);
   Expect.equals(1, dt.day);
   Expect.equals(dtBase.hour, dt.hour);
   Expect.equals(dtBase.minute, dt.minute);
   Expect.equals(dtBase.second, dt.second);
   Expect.equals(dtBase.millisecond, dt.millisecond);
+  Expect.equals(dtBase.microsecond, dt.microsecond);
 
   // Month
   print("  >>> Month+");
   dt = new DateTime(dtBase.year, 13, dtBase.day, dtBase.hour, dtBase.minute,
-                dtBase.second, dtBase.millisecond);
+                dtBase.second, dtBase.millisecond, dtBase.microsecond);
   Expect.equals(dtBase.year + 1, dt.year);
   Expect.equals(1, dt.month);
   Expect.equals(dtBase.day, dt.day);
   Expect.equals(dtBase.hour, dt.hour);
   Expect.equals(dtBase.minute, dt.minute);
   Expect.equals(dtBase.second, dt.second);
   Expect.equals(dtBase.millisecond, dt.millisecond);
+  Expect.equals(dtBase.microsecond, dt.microsecond);
 
   print("  >>> Month-");
   dt = new DateTime(dtBase.year, -11, dtBase.day, dtBase.hour, dtBase.minute,
-                dtBase.second, dtBase.millisecond);
+                dtBase.second, dtBase.millisecond, dtBase.microsecond);
   Expect.equals(dtBase.year - 1, dt.year);
   Expect.equals(1, dt.month);
   Expect.equals(dtBase.day, dt.day);
   Expect.equals(dtBase.hour, dt.hour);
   Expect.equals(dtBase.minute, dt.minute);
   Expect.equals(dtBase.second, dt.second);
   Expect.equals(dtBase.millisecond, dt.millisecond);
+  Expect.equals(dtBase.microsecond, dt.microsecond);
 
   // Flowing all the way up the chain.
   print("  >>> Flow+");
-  var dtBase1 = new DateTime(2012, 12, 31, 23, 59, 59, 999);
+  var dtBase1 = new DateTime(2012, 12, 31, 23, 59, 59, 999, 000);
   var dtTick = new DateTime(dtBase1.year, dtBase1.month, dtBase1.day,
                         dtBase1.hour, dtBase1.minute, dtBase1.second,
-                        dtBase1.millisecond + 1);
+                        dtBase1.millisecond + 1, dtBase1.microsecond);
   Expect.equals(dtBase1.year + 1, dtTick.year);
   Expect.equals(1, dtTick.month);
   Expect.equals(1, dtTick.day);
   Expect.equals(0, dtTick.hour);
   Expect.equals(0, dtTick.minute);
   Expect.equals(0, dtTick.second);
   Expect.equals(0, dtTick.millisecond);
+  Expect.equals(0, dtTick.microsecond);
 
   print("  >>> Flow-");
   dtBase1 = new DateTime(2012, 1, 1, 0, 0, 0, 0);
   dtTick = new DateTime(dtBase1.year, dtBase1.month, dtBase1.day, dtBase1.hour,
-                    dtBase1.minute, dtBase1.second, dtBase1.millisecond - 1);
+                    dtBase1.minute, dtBase1.second, dtBase1.millisecond - 1,
+                    dtBase1.microsecond);
   Expect.equals(dtBase1.year - 1, dtTick.year);
   Expect.equals(12, dtTick.month);
   Expect.equals(31, dtTick.day);
   Expect.equals(23, dtTick.hour);
   Expect.equals(59, dtTick.minute);
   Expect.equals(59, dtTick.second);
   Expect.equals(999, dtTick.millisecond);
+  Expect.equals(0, dtTick.microsecond);
 
   print("  >>> extra underflow");
   dtTick = new DateTime(dtBase1.year, dtBase1.month, dtBase1.day, -17520,
-                    dtBase1.minute, dtBase1.second, dtBase1.millisecond);
+                    dtBase1.minute, dtBase1.second, dtBase1.millisecond,
+                    dtBase1.microsecond);
   Expect.equals(dtBase1.year - 2, dtTick.year);
   Expect.equals(dtBase1.month, dtTick.month);
   Expect.equals(dtBase1.day, dtTick.day);
   Expect.equals(dtBase1.hour, dtTick.hour);
   Expect.equals(dtBase1.minute, dtTick.minute);
   Expect.equals(dtBase1.second, dtTick.second);
   Expect.equals(dtBase1.millisecond, dtTick.millisecond);
+  Expect.equals(dtBase1.microsecond, dtTick.microsecond);
+
+  if (!supportsMicroseconds) return;
+
+  // Microsecond
+  print("  >>> Microsecond+");
+  dt = new DateTime(dtBase.year, dtBase.month, dtBase.day, dtBase.hour,
+                    dtBase.minute, dtBase.second, dtBase.millisecond, 1000);
+  Expect.equals(dtBase.year, dt.year);
+  Expect.equals(dtBase.month, dt.month);
+  Expect.equals(dtBase.day, dt.day);
+  Expect.equals(dtBase.hour, dt.hour);
+  Expect.equals(dtBase.minute, dt.minute);
+  Expect.equals(dtBase.second, dt.second);
+  Expect.equals(dtBase.millisecond + 1, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
+
+  print("  >>> Microsecond-");
+  dt = new DateTime(dtBase.year, dtBase.month, dtBase.day, dtBase.hour,
+                dtBase.minute, dtBase.second, dtBase.millisecond, -1000);
+  Expect.equals(dtBase.year, dt.year);
+  Expect.equals(dtBase.month, dt.month);
+  Expect.equals(dtBase.day, dt.day);
+  Expect.equals(dtBase.hour, dt.hour);
+  Expect.equals(dtBase.minute, dt.minute);
+  Expect.equals(dtBase.second, dt.second);
+  Expect.equals(dtBase.millisecond - 1, dt.millisecond);
+  Expect.equals(0, dt.microsecond);
+
+  // Flowing all the way up the chain.
+  print("  >>> Flow+ 2");
+  dtBase1 = new DateTime(2012, 12, 31, 23, 59, 59, 999, 999);
+  dtTick = new DateTime(dtBase1.year, dtBase1.month, dtBase1.day,
+                        dtBase1.hour, dtBase1.minute, dtBase1.second,
+                        dtBase1.millisecond, dtBase1.microsecond + 1);
+  Expect.equals(dtBase1.year + 1, dtTick.year);
+  Expect.equals(1, dtTick.month);
+  Expect.equals(1, dtTick.day);
+  Expect.equals(0, dtTick.hour);
+  Expect.equals(0, dtTick.minute);
+  Expect.equals(0, dtTick.second);
+  Expect.equals(0, dtTick.millisecond);
+  Expect.equals(0, dtTick.microsecond);
+
+  print("  >>> Flow- 2");
+  dtBase1 = new DateTime(2012, 1, 1, 0, 0, 0, 0, 0);
+  dtTick = new DateTime(dtBase1.year, dtBase1.month, dtBase1.day, dtBase1.hour,
+                    dtBase1.minute, dtBase1.second, dtBase1.millisecond,
+                    dtBase1.microsecond - 1);
+  Expect.equals(dtBase1.year - 1, dtTick.year);
+  Expect.equals(12, dtTick.month);
+  Expect.equals(31, dtTick.day);
+  Expect.equals(23, dtTick.hour);
+  Expect.equals(59, dtTick.minute);
+  Expect.equals(59, dtTick.second);
+  Expect.equals(999, dtTick.millisecond);
+  Expect.equals(999, dtTick.microsecond);
 }
 
 void testDateStrings() {
   // TODO(floitsch): Clean up the DateTime API that deals with strings.
   var dt1 = DateTime.parse("2011-05-11 18:58:35Z");
   Expect.equals(1305140315000, dt1.millisecondsSinceEpoch);
   Expect.isTrue(dt1.isUtc);
   dt1 = DateTime.parse("20110511 18:58:35z");
   Expect.equals(1305140315000, dt1.millisecondsSinceEpoch);
   Expect.isTrue(dt1.isUtc);
   dt1 = DateTime.parse("+20110511 18:58:35z");
   Expect.equals(1305140315000, dt1.millisecondsSinceEpoch);
   Expect.isTrue(dt1.isUtc);
   var str = dt1.toString();
   var dt2 = DateTime.parse(str);
   Expect.equals(true, dt1 == dt2);
   var dt3 = dt1.toUtc();
   str = dt3.toString();
   Expect.equals("2011-05-11 18:58:35.000Z", str);
   var dt4 = DateTime.parse("-1234-01-01 00:00:00Z");
   Expect.equals(-1234, dt4.year);
   Expect.equals(1, dt4.month);
   Expect.equals(1, dt4.day);
   Expect.equals(0, dt4.hour);
   Expect.equals(0, dt4.minute);
   Expect.equals(0, dt4.second);
   Expect.equals(0, dt4.millisecond);
+  Expect.equals(0, dt4.microsecond);
   Expect.isTrue(dt4.isUtc);
   var dt5 = DateTime.parse("0099-01-02");
   Expect.equals(99, dt5.year);
   Expect.equals(1, dt5.month);
   Expect.equals(2, dt5.day);
   Expect.equals(0, dt5.hour);
   Expect.equals(0, dt5.minute);
   Expect.equals(0, dt5.second);
   Expect.equals(0, dt5.millisecond);
+  Expect.equals(0, dt5.microsecond);
   Expect.isFalse(dt5.isUtc);
   var dt6 = DateTime.parse("2012-01-01 00:00:10.012");
   Expect.equals(12, dt6.millisecond);
+  Expect.equals(0, dt6.microsecond);
   dt6 = DateTime.parse("2012-01-01 00:00:10.003");
   Expect.equals(3, dt6.millisecond);
+  Expect.equals(0, dt6.microsecond);
   dt6 = DateTime.parse("2012-01-01 00:00:10.5");
   Expect.equals(500, dt6.millisecond);
+  Expect.equals(0, dt6.microsecond);
   dt6 = DateTime.parse("2012-01-01 00:00:10.003Z");
   Expect.equals(3, dt6.millisecond);
+  Expect.equals(0, dt6.microsecond);
   dt6 = DateTime.parse("2012-01-01 00:00:10.5z");
   Expect.equals(500, dt6.millisecond);
+  Expect.equals(0, dt6.microsecond);
   var dt7 = DateTime.parse("2011-05-11T18:58:35Z");
   Expect.equals(1305140315000, dt7.millisecondsSinceEpoch);
   var dt8 = DateTime.parse("-1234-01-01T00:00:00Z");
   Expect.equals(-1234, dt8.year);
   Expect.equals(1, dt8.month);
   Expect.equals(1, dt8.day);
   Expect.equals(0, dt8.hour);
   Expect.equals(0, dt8.minute);
   Expect.equals(0, dt8.second);
   Expect.equals(0, dt8.millisecond);
+  Expect.equals(0, dt8.microsecond);
   Expect.isTrue(dt8.isUtc);
   var dt9 = DateTime.parse("-1234-01-01T00:00:00");
   Expect.equals(-1234, dt9.year);
   Expect.equals(1, dt9.month);
   Expect.equals(1, dt9.day);
   Expect.equals(0, dt9.hour);
   Expect.equals(0, dt9.minute);
   Expect.equals(0, dt9.second);
   Expect.equals(0, dt9.millisecond);
+  Expect.equals(0, dt9.microsecond);
   Expect.isFalse(dt9.isUtc);
   var dt10 = DateTime.parse("-12340101");
   Expect.equals(-1234, dt10.year);
   Expect.equals(1, dt10.month);
   Expect.equals(1, dt10.day);
   Expect.equals(0, dt10.hour);
   Expect.equals(0, dt10.minute);
   Expect.equals(0, dt10.second);
   Expect.equals(0, dt10.millisecond);
+  Expect.equals(0, dt10.microsecond);
   Expect.isFalse(dt10.isUtc);
   dt1 = DateTime.parse("2012-02-27 13:27:00");
   Expect.equals(2012, dt1.year);
   Expect.equals(2, dt1.month);
   Expect.equals(27, dt1.day);
   Expect.equals(13, dt1.hour);
   Expect.equals(27, dt1.minute);
   Expect.equals(0, dt1.second);
   Expect.equals(0, dt1.millisecond);
+  Expect.equals(0, dt1.microsecond);
   Expect.equals(false, dt1.isUtc);
   dt1 = DateTime.parse("2012-02-27 13:27:00.423z");
   Expect.equals(2012, dt1.year);
   Expect.equals(2, dt1.month);
   Expect.equals(27, dt1.day);
   Expect.equals(13, dt1.hour);
   Expect.equals(27, dt1.minute);
   Expect.equals(0, dt1.second);
   Expect.equals(423, dt1.millisecond);
+  Expect.equals(0, dt1.microsecond);
   Expect.equals(true, dt1.isUtc);
   dt1 = DateTime.parse("20120227 13:27:00");
   Expect.equals(2012, dt1.year);
   Expect.equals(2, dt1.month);
   Expect.equals(27, dt1.day);
   Expect.equals(13, dt1.hour);
   Expect.equals(27, dt1.minute);
   Expect.equals(0, dt1.second);
   Expect.equals(0, dt1.millisecond);
+  Expect.equals(0, dt1.microsecond);
   Expect.equals(false, dt1.isUtc);
   dt1 = DateTime.parse("20120227T132700");
   Expect.equals(2012, dt1.year);
   Expect.equals(2, dt1.month);
   Expect.equals(27, dt1.day);
   Expect.equals(13, dt1.hour);
   Expect.equals(27, dt1.minute);
   Expect.equals(0, dt1.second);
   Expect.equals(0, dt1.millisecond);
+  Expect.equals(0, dt1.microsecond);
   Expect.equals(false, dt1.isUtc);
   dt1 = DateTime.parse("20120227");
   Expect.equals(2012, dt1.year);
   Expect.equals(2, dt1.month);
   Expect.equals(27, dt1.day);
   Expect.equals(0, dt1.hour);
   Expect.equals(0, dt1.minute);
   Expect.equals(0, dt1.second);
   Expect.equals(0, dt1.millisecond);
+  Expect.equals(0, dt1.microsecond);
   Expect.equals(false, dt1.isUtc);
   dt1 = DateTime.parse("2012-02-27T14Z");
   Expect.equals(2012, dt1.year);
   Expect.equals(2, dt1.month);
   Expect.equals(27, dt1.day);
   Expect.equals(14, dt1.hour);
   Expect.equals(0, dt1.minute);
   Expect.equals(0, dt1.second);
   Expect.equals(0, dt1.millisecond);
+  Expect.equals(0, dt1.microsecond);
   Expect.equals(true, dt1.isUtc);
   dt1 = DateTime.parse("-123450101 00:00:00 Z");
   Expect.equals(-12345, dt1.year);
   Expect.equals(1, dt1.month);
   Expect.equals(1, dt1.day);
   Expect.equals(0, dt1.hour);
   Expect.equals(0, dt1.minute);
   Expect.equals(0, dt1.second);
   Expect.equals(0, dt1.millisecond);
+  Expect.equals(0, dt1.microsecond);
   Expect.equals(true, dt1.isUtc);
-  // We only support millisecond. If the user supplies more data (the "51"
-  // here), we round.
-  // If (eventually) we support more than just millisecond this test could
-  // fail. Please update the test in this case.
   dt1 = DateTime.parse("1999-01-02 23:59:59.99951");
-  Expect.equals(1999, dt1.year);
-  Expect.equals(1, dt1.month);
-  Expect.equals(3, dt1.day);
-  Expect.equals(0, dt1.hour);
-  Expect.equals(0, dt1.minute);
-  Expect.equals(0, dt1.second);
-  Expect.equals(0, dt1.millisecond);
+  if (supportsMicroseconds) {
+    Expect.equals(1999, dt1.year);
+    Expect.equals(1, dt1.month);
+    Expect.equals(2, dt1.day);
+    Expect.equals(23, dt1.hour);
+    Expect.equals(59, dt1.minute);
+    Expect.equals(59, dt1.second);
+    Expect.equals(999, dt1.millisecond);
+    Expect.equals(510, dt1.microsecond);
+  } else {
+    // We only support millisecond. If the user supplies more data (the "51"
+    // here), we round.
+    Expect.equals(1999, dt1.year);
+    Expect.equals(1, dt1.month);
+    Expect.equals(3, dt1.day);
+    Expect.equals(0, dt1.hour);
+    Expect.equals(0, dt1.minute);
+    Expect.equals(0, dt1.second);
+    Expect.equals(0, dt1.millisecond);
+    Expect.equals(0, dt1.microsecond);
+  }
   Expect.equals(false, dt1.isUtc);
   dt1 = DateTime.parse("1999-01-02 23:58:59.99951Z");
-  Expect.equals(1999, dt1.year);
-  Expect.equals(1, dt1.month);
-  Expect.equals(2, dt1.day);
-  Expect.equals(23, dt1.hour);
-  Expect.equals(59, dt1.minute);
-  Expect.equals(0, dt1.second);
-  Expect.equals(0, dt1.millisecond);
+  if (supportsMicroseconds) {
+    Expect.equals(1999, dt1.year);
+    Expect.equals(1, dt1.month);
+    Expect.equals(2, dt1.day);
+    Expect.equals(23, dt1.hour);
+    Expect.equals(58, dt1.minute);
+    Expect.equals(59, dt1.second);
+    Expect.equals(999, dt1.millisecond);
+    Expect.equals(510, dt1.microsecond);
+  } else {
+    Expect.equals(1999, dt1.year);
+    Expect.equals(1, dt1.month);
+    Expect.equals(2, dt1.day);
+    Expect.equals(23, dt1.hour);
+    Expect.equals(59, dt1.minute);
+    Expect.equals(0, dt1.second);
+    Expect.equals(0, dt1.millisecond);
+    Expect.equals(0, dt1.microsecond);
+  }
   Expect.equals(true, dt1.isUtc);
   dt1 = DateTime.parse("0009-09-09 09:09:09.009Z");
   Expect.equals(9, dt1.year);
   Expect.equals(9, dt1.month);
   Expect.equals(9, dt1.day);
   Expect.equals(9, dt1.hour);
   Expect.equals(9, dt1.minute);
   Expect.equals(9, dt1.second);
   Expect.equals(9, dt1.millisecond);
   Expect.equals(true, dt1.isUtc);
@@ skipping 73 matching lines @@
   Expect.throws(() => DateTime.parse("bad"), (e) => e is FormatException);
   var bad_year = 1970 + (_MAX_MILLISECONDS ~/ (1000*60*60*24*365.2425)) + 1;
   Expect.throws(() => DateTime.parse(bad_year.toString() + "-01-01"),
                 (e) => e is FormatException);
   // The last valid time; should not throw.
   dt1 = DateTime.parse("275760-09-13T00:00:00.000Z");
   Expect.throws(() => DateTime.parse("275760-09-14T00:00:00.000Z"),
                 (e) => e is FormatException);
   Expect.throws(() => DateTime.parse("275760-09-13T00:00:00.001Z"),
                 (e) => e is FormatException);
+  if (supportsMicroseconds) {
+    Expect.throws(() => DateTime.parse("275760-09-13T00:00:00.000001Z"),
+                  (e) => e is FormatException);
+  } else {
+    dt1 = DateTime.parse("275760-09-13T00:00:00.000001Z");
+  }
 
   // first valid time; should not throw.
   dt1 = DateTime.parse("-271821-04-20T00:00:00.000Z");
   Expect.throws(() => DateTime.parse("-271821-04-19T23:59:59.999Z"),
                 (e) => e is FormatException);
+
+  if (supportsMicroseconds) {
+    Expect.throws(() => DateTime.parse("-271821-04-19T23:59:59.999999Z"),
+                  (e) => e is FormatException);
+  }
 }
 
 void testWeekday() {
   // 2011-10-06 is Summertime.
   var d = new DateTime(2011, 10, 6, 0, 45, 37, 0);
   Expect.equals(DateTime.THURSDAY, d.weekday);
   d = new DateTime.utc(2011, 10, 6, 0, 45, 37, 0);
   Expect.equals(DateTime.THURSDAY, d.weekday);
   d = new DateTime(2011, 10, 5, 23, 45, 37, 0);
   Expect.equals(DateTime.WEDNESDAY, d.weekday);
@@ skipping 41 matching lines @@
       Expect.equals(utcTime1, utcTime2);
       Expect.equals(source1, utcTime1.toString());
       Expect.equals(source2, utcTime1.toIso8601String());
     }
   }
   test("2000-01-01", "12:00:00.000");
   test("-2000-01-01", "12:00:00.000");
   test("1970-01-01", "00:00:00.000");
   test("1969-12-31", "23:59:59.999");
   test("1969-09-09", "00:09:09.009");
+
+  if (supportsMicroseconds) {
+    test("2000-01-01", "12:00:00.000001");
+    test("-2000-01-01", "12:00:00.000001");
+    test("1970-01-01", "00:00:00.000001");
+    test("1969-12-31", "23:59:59.999999");
+    test("1969-09-09", "00:09:09.009999");
+  }
 }
 
 void testIsoString() {
   var d = new DateTime(9999, 1, 1, 23, 59, 59, 999);
   Expect.equals("9999-01-01T23:59:59.999", d.toIso8601String());
   d = new DateTime(-9999, 1, 1, 23, 59, 59, 999);
   Expect.equals("-9999-01-01T23:59:59.999", d.toIso8601String());
   d = new DateTime.utc(9999, 1, 1, 23, 59, 59, 999);
   Expect.equals("9999-01-01T23:59:59.999Z", d.toIso8601String());
   d = new DateTime.utc(-9999, 1, 1, 23, 59, 59, 999);
   Expect.equals("-9999-01-01T23:59:59.999Z", d.toIso8601String());
 
   d = new DateTime(10000, 1, 1, 23, 59, 59, 999);
   Expect.equals("+010000-01-01T23:59:59.999", d.toIso8601String());
   d = new DateTime(-10000, 1, 1, 23, 59, 59, 999);
   Expect.equals("-010000-01-01T23:59:59.999", d.toIso8601String());
   d = new DateTime.utc(10000, 1, 1, 23, 59, 59, 999);
   Expect.equals("+010000-01-01T23:59:59.999Z", d.toIso8601String());
   d = new DateTime.utc(-10000, 1, 1, 23, 59, 59, 999);
   Expect.equals("-010000-01-01T23:59:59.999Z", d.toIso8601String());
+
+  if (!supportsMicroseconds) return;
+
+  d = new DateTime(9999, 1, 1, 23, 59, 59, 999, 999);
+  Expect.equals("9999-01-01T23:59:59.999999", d.toIso8601String());
+  d = new DateTime(-9999, 1, 1, 23, 59, 59, 999, 999);
+  Expect.equals("-9999-01-01T23:59:59.999999", d.toIso8601String());
+  d = new DateTime.utc(9999, 1, 1, 23, 59, 59, 999, 999);
+  Expect.equals("9999-01-01T23:59:59.999999Z", d.toIso8601String());
+  d = new DateTime.utc(-9999, 1, 1, 23, 59, 59, 999, 999);
+  Expect.equals("-9999-01-01T23:59:59.999999Z", d.toIso8601String());
+
+  d = new DateTime(10000, 1, 1, 23, 59, 59, 999, 999);
+  Expect.equals("+010000-01-01T23:59:59.999999", d.toIso8601String());
+  d = new DateTime(-10000, 1, 1, 23, 59, 59, 999, 999);
+  Expect.equals("-010000-01-01T23:59:59.999999", d.toIso8601String());
+  d = new DateTime.utc(10000, 1, 1, 23, 59, 59, 999, 999);
+  Expect.equals("+010000-01-01T23:59:59.999999Z", d.toIso8601String());
+  d = new DateTime.utc(-10000, 1, 1, 23, 59, 59, 999, 999);
+  Expect.equals("-010000-01-01T23:59:59.999999Z", d.toIso8601String());
+
+  d = new DateTime(9999, 1, 1, 23, 49, 59, 989, 979);
+  Expect.equals("9999-01-01T23:49:59.989979", d.toIso8601String());
+  d = new DateTime(-9999, 1, 1, 23, 49, 59, 989, 979);
+  Expect.equals("-9999-01-01T23:49:59.989979", d.toIso8601String());
+  d = new DateTime.utc(9999, 1, 1, 23, 49, 59, 989, 979);
+  Expect.equals("9999-01-01T23:49:59.989979Z", d.toIso8601String());
+  d = new DateTime.utc(-9999, 1, 1, 23, 49, 59, 989, 979);
+  Expect.equals("-9999-01-01T23:49:59.989979Z", d.toIso8601String());
+
+  d = new DateTime(10000, 1, 1, 23, 49, 59, 989, 979);
+  Expect.equals("+010000-01-01T23:49:59.989979", d.toIso8601String());
+  d = new DateTime(-10000, 1, 1, 23, 49, 59, 989, 979);
+  Expect.equals("-010000-01-01T23:49:59.989979", d.toIso8601String());
+  d = new DateTime.utc(10000, 1, 1, 23, 49, 59, 989, 979);
+  Expect.equals("+010000-01-01T23:49:59.989979Z", d.toIso8601String());
+  d = new DateTime.utc(-10000, 1, 1, 23, 49, 59, 989, 979);
+  Expect.equals("-010000-01-01T23:49:59.989979Z", d.toIso8601String());
 }
 
 void main() {
   testNow();
-  testValue();
+  testMillisecondsSinceEpoch();
+  testMicrosecondsSinceEpoch();
   testConstructors();
   testUTCGetters();
   testLocalGetters();
   testChangeTimeZone();
   testSubAdd();
   testUnderflowAndOverflow();
   testDateStrings();
   testEquivalentYears();
   testExtremes();
   testFarAwayDates();
   testWeekday();
   testToStrings();
   testIsoString();
 }