Change DateTime.parse FormatException messages; update tests

tests/corelib/date_time_test.dart

Index: tests/corelib/date_time_test.dart
diff --git a/tests/corelib/date_time_test.dart b/tests/corelib/date_time_test.dart
index e9fc4783e18f985018616b8d02b51c94500ef969..b9fb7da1d7beb5daf9204997f4dbc23989ce60f4 100644
--- a/tests/corelib/date_time_test.dart
+++ b/tests/corelib/date_time_test.dart
@@ -6,6 +6,9 @@ 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();
@@ -232,7 +235,7 @@ void testEquivalentYears() {
 
 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);
@@ -240,7 +243,7 @@ void testExtremes() {
   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);
@@ -249,28 +252,30 @@ void testExtremes() {
   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));
 }
@@ -848,6 +853,11 @@ void testDateStrings() {
   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() {