time: clarify documentation for allowed formats and add tests to prove them

The existing documentation for the time.Layout const states "Only these values
are recognized", but then doesn't include the numeric forms for month leading to
ambiguity and assumptions that may not be true. It's unclear, for example,
that space padding is only available for day of the month.

Finally I add tests to show the behaviors in specific scenarios.

Change-Id: I4e08a14834c17b6bdf3b6b47d39dafa8c1a138fb
Reviewed-on: https://go-review.googlesource.com/c/go/+/418875
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Ian Lance Taylor <iant@google.com>

diff --git a/src/time/format.go b/src/time/format.go
index 5f696189ff114ff0cc6204a04f69a4b3d71b33ea..8431ff89b45360571b3d4bc681cae894e0544af1 100644 (file)
--- a/src/time/format.go
+++ b/src/time/format.go
@@ -53,10 +53,10 @@ import "errors"
 // verbatim in the input to Parse.
 //
 //     Year: "2006" "06"
-//     Month: "Jan" "January"
-//     Textual day of the week: "Mon" "Monday"
-//     Numeric day of the month: "2" "_2" "02"
-//     Numeric day of the year: "__2" "002"
+//     Month: "Jan" "January" "01" "1"
+//     Day of the week: "Mon" "Monday"
+//     Day of the month: "2" "_2" "02"
+//     Day of the year: "__2" "002"
 //     Hour: "15" "3" "03" (PM or AM)
 //     Minute: "4" "04"
 //     Second: "5" "05"

diff --git a/src/time/format_test.go b/src/time/format_test.go
index ab72fae32318191a834957c1c925f07559dd553e..9ae2b8017a3bb5e9df8e6fdfa0dd0d058b43d0bd 100644 (file)
--- a/src/time/format_test.go
+++ b/src/time/format_test.go
@@ -116,6 +116,13 @@ var formatTests = []FormatTest{
        {"StampMicro", StampMicro, "Feb  4 21:00:57.012345"},
        {"StampNano", StampNano, "Feb  4 21:00:57.012345600"},
        {"YearDay", "Jan  2 002 __2 2", "Feb  4 035  35 4"},
+       {"Year", "2006 6 06 _6 __6 ___6", "2009 6 09 _6 __6 ___6"},
+       {"Month", "Jan January 1 01 _1", "Feb February 2 02 _2"},
+       {"DayOfMonth", "2 02 _2 __2", "4 04  4  35"},
+       {"DayOfWeek", "Mon Monday", "Wed Wednesday"},
+       {"Hour", "15 3 03 _3", "21 9 09 _9"},
+       {"Minute", "4 04 _4", "0 00 _0"},
+       {"Second", "5 05 _5", "57 57 _57"},
 }
 
 func TestFormat(t *testing.T) {