fix(filter:date) Timezone formatting issues.

This commit fixes angular#1261 and angular#1532. This covers
two separate issues:

- Positive timezones were being formatted without
a leading `+` resulting in a formatting string
like: "HH:MM:ssZ" giving "12:13:141000" instead
of "12:13:14+1000". Fixed by checking if timezone
is > 0 and adding a leading "+".

- Timezone output signs were inverted.
mock.TzDate expects the timezone _offset_ as it's
first argument, _not_ the timezone. This means
that a mock.TzDate with a positive offset should
result in a date string with a negative timezone,
and vice-versa.

src/ng/filter/filters.js

@@ -212,7 +212,18 @@ function dateStrGetter(name, shortForm) {
 
 function timeZoneGetter(date) {
   var offset = date.getTimezoneOffset();
-  return padNumber(offset / 60, 2) + padNumber(Math.abs(offset % 60), 2);
+  var zone = -1 * offset;
+  var paddedZone;
+  if (zone === 0) {
+    return "Z";
+  } else {
+    paddedZone = padNumber(zone / 60, 2) + padNumber(Math.abs(zone % 60), 2);
+
+    if (zone > 0)
+      paddedZone = "+"+paddedZone;
+
+    return paddedZone;
+  }
 }
 
 function ampmGetter(date, formats) {
@@ -319,7 +330,7 @@ var DATE_FORMATS_SPLIT = /((?:[^yMdHhmsaZE']+)|(?:'(?:[^']|'')*')|(?:E+|y+|M+|d+
          expect(binding("1288323623006 | date:'medium'")).
             toMatch(/Oct 2\d, 2010 \d{1,2}:\d{2}:\d{2} (AM|PM)/);
          expect(binding("1288323623006 | date:'yyyy-MM-dd HH:mm:ss Z'")).
-            toMatch(/2010\-10\-2\d \d{2}:\d{2}:\d{2} \-?\d{4}/);
+            toMatch(/2010\-10\-2\d \d{2}:\d{2}:\d{2} (\-|\+)?\d{4}/);
          expect(binding("'1288323623006' | date:'MM/dd/yyyy @ h:mma'")).
             toMatch(/10\/2\d\/2010 @ \d{1,2}:\d{2}(AM|PM)/);
        });

test/ng/filter/filtersSpec.js

@@ -193,13 +193,13 @@ describe('filters', function() {
                       toEqual('10-09-03 07:05:08');
 
       expect(date(midnight, "yyyy-M-d h=H:m:saZ")).
-                      toEqual('2010-9-3 12=0:5:8AM0500');
+                      toEqual('2010-9-3 12=0:5:8AM-0500');
 
       expect(date(midnight, "yyyy-MM-dd hh=HH:mm:ssaZ")).
-                      toEqual('2010-09-03 12=00:05:08AM0500');
+                      toEqual('2010-09-03 12=00:05:08AM-0500');
 
       expect(date(noon, "yyyy-MM-dd hh=HH:mm:ssaZ")).
-                      toEqual('2010-09-03 12=12:05:08PM0500');
+                      toEqual('2010-09-03 12=12:05:08PM-0500');
 
       expect(date(noon, "EEE, MMM d, yyyy")).
                       toEqual('Fri, Sep 3, 2010');
@@ -209,16 +209,36 @@ describe('filters', function() {
 
       expect(date(earlyDate, "MMMM dd, y")).
                       toEqual('September 03, 1');
+
+    });
+
+    it('should format timezones correctly (as per ISO_8601)', function() {
+      //Note: TzDate's first argument is offset, _not_ timezone.
+      var utc       = new angular.mock.TzDate( 0, '2010-09-03T12:05:08.000Z');
+      var eastOfUTC = new angular.mock.TzDate(-5, '2010-09-03T12:05:08.000Z');
+      var westOfUTC = new angular.mock.TzDate(+5, '2010-09-03T12:05:08.000Z');
+
+      expect(date(utc, "yyyy-MM-ddTHH:mm:ssZ")).
+                    toEqual('2010-09-03T12:05:08Z')
+
+      expect(date(eastOfUTC, "yyyy-MM-ddTHH:mm:ssZ")).
+                    toEqual('2010-09-03T17:05:08+0500')
+
+      expect(date(westOfUTC, "yyyy-MM-ddTHH:mm:ssZ")).
+                    toEqual('2010-09-03T07:05:08-0500')
+
     });
 
+
+
     it('should treat single quoted strings as string literals', function() {
       expect(date(midnight, "yyyy'de' 'a'x'dd' 'adZ' h=H:m:saZ")).
-                      toEqual('2010de axdd adZ 12=0:5:8AM0500');
+                      toEqual('2010de axdd adZ 12=0:5:8AM-0500');
     });
 
     it('should treat a sequence of two single quotes as a literal single quote', function() {
       expect(date(midnight, "yyyy'de' 'a''dd' 'adZ' h=H:m:saZ")).
-                      toEqual("2010de a'dd adZ 12=0:5:8AM0500");
+                      toEqual("2010de a'dd adZ 12=0:5:8AM-0500");
     });
 
     it('should accept default formats', function() {
@@ -274,6 +294,7 @@ describe('filters', function() {
     });
 
 
+
     it('should parse iso8061 date strings without timezone as local time', function() {
       var format = 'yyyy-MM-dd HH-mm-ss';
 
@@ -298,5 +319,7 @@ describe('filters', function() {
       expect(date('2003-09-10T13:02:03.12Z', format)).toEqual('2003-09-10');
       expect(date('2003-09-10T13:02:03.1Z', format)).toEqual('2003-09-10');
     });
+
+
   });
 });