Change DateTime.parse FormatException messages; update tests

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.
 
+// 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;
   for (int i = 0; i < 1000000; i++) {
     var t2 = new DateTime.now();
     if (t1.millisecondsSinceEpoch < t2.millisecondsSinceEpoch) {
       timeMovedForward = true;
       break;
     }
@@ skipping 206 matching lines @@
   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("2036-07-18 13:20:00.000", dt.toString());
 }
 
 void testExtremes() {
   var dt =
-      new DateTime.fromMillisecondsSinceEpoch(8640000000000000, isUtc: true);
+      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);
-  dt = new DateTime.fromMillisecondsSinceEpoch(-8640000000000000, isUtc: true);
+  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);
   // Make sure that we can build the extreme dates in local too.
-  dt = new DateTime.fromMillisecondsSinceEpoch(8640000000000000);
+  dt = new DateTime.fromMillisecondsSinceEpoch(_MAX_MILLISECONDS);
   dt = new DateTime(dt.year, dt.month, dt.day, dt.hour, dt.minute);
-  Expect.equals(8640000000000000, dt.millisecondsSinceEpoch);
-  dt = new DateTime.fromMillisecondsSinceEpoch(-8640000000000000);
+  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(-8640000000000000, dt.millisecondsSinceEpoch);
-  Expect.throws(() => new DateTime.fromMillisecondsSinceEpoch(8640000000000001,
-                                                          isUtc: true));
-  Expect.throws(() => new DateTime.fromMillisecondsSinceEpoch(-8640000000000001,
-                                                          isUtc: true));
-  Expect.throws(() => new DateTime.fromMillisecondsSinceEpoch(8640000000000001));
-  Expect.throws(() => new DateTime.fromMillisecondsSinceEpoch(-8640000000000001));
-  dt = new DateTime.fromMillisecondsSinceEpoch(8640000000000000);
+  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(8640000000000000, isUtc: true);
+  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(-8640000000000000);
+  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(-8640000000000000, isUtc: true);
+  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));
 }
 
 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);
@@ skipping 557 matching lines @@
   Expect.equals(true, dt1.isUtc);
   dt1 = DateTime.parse("0009-09-09 09:09:09.009-2134");
   Expect.equals(9, dt1.year);
   Expect.equals(9, dt1.month);
   Expect.equals(10, dt1.day);
   Expect.equals(6, dt1.hour);
   Expect.equals(43, dt1.minute);
   Expect.equals(9, dt1.second);
   Expect.equals(9, dt1.millisecond);
   Expect.equals(true, dt1.isUtc);
+
+  Expect.throws(() => DateTime.parse("bad"), (e) => e is FormatException);
+  var bad_year = _MAX_MILLISECONDS ~/ 60 ~/ 60 ~/ 24 ~/ 365 + 10;
+  Expect.throws(() => DateTime.parse(bad_year.toString() + "-1-1"),

[Lasse Reichstein Nielsen, 2014/08/04 07:25:47]

make it "-01-01", just so the reader (me) doesn't have to wonder whether
something like 1970-1-1 is a valid date. I actually think it isn't, so that
alone should give the format exception.

Shouldn't this be 1970 based somehow? 
It seems to work anyway because you only divide by 365, not 365.2425 (avg.
days/year in a 400 year cycle).

Try using:
  bad_year = 1970 + (_MAX_MILLISECONDS ~/ 1000*60*60*24*365.2425) + 1;
(which is year 275761)
So this also fails because we only accept up to 5-digit years. Change this in
datetime.dart so that this test is meaningful.

The first invalid *day* is actually
  +275760-09-14
so check that 09-13 works and -09-14 fails (and so does
"275760-09-13T00:00:00.001Z")

For negative dates, use -271821-04-20Z (good) and "-271821-04-19T23:59:59.999Z"
(bad).

[srawlins, 2014/08/04 19:58:30]

Thanks so much for these tips, lrn@! I've added the tests you suggested, and
tweaked the RegExp to accept 6-digit years. I think all is good now.

+                (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 59 matching lines @@
   testChangeTimeZone();
   testSubAdd();
   testUnderflowAndOverflow();
   testDateStrings();
   testEquivalentYears();
   testExtremes();
   testFarAwayDates();
   testWeekday();
   testToStrings();
 }