[PATCH 2/3] t0006: test various date formats

[Jeff King <peff@peff.net>]

We ended up testing some of these date formats throughout
the rest of the suite (e.g., via for-each-ref's
"$(authordate:...)" format), but we never did so
systematically. t0006 is the right place for unit-testing of
our date-handling code.

Signed-off-by: Jeff King <peff@peff.net>
---
 t/helper/test-date.c | 26 ++++++++++++++++++++++++++
 t/t0006-date.sh      | 21 +++++++++++++++++++++
 2 files changed, 47 insertions(+)

diff --git a/t/helper/test-date.c b/t/helper/test-date.c
index 8ebcded..d9ab360 100644
--- a/t/helper/test-date.c
+++ b/t/helper/test-date.c
@@ -2,6 +2,7 @@
 
 static const char *usage_msg = "\n"
 "  test-date relative [time_t]...\n"
+"  test-date show:<format> [time_t]...\n"
 "  test-date parse [date]...\n"
 "  test-date approxidate [date]...\n";
 
@@ -17,6 +18,29 @@ static void show_relative_dates(char **argv, struct timeval *now)
 	strbuf_release(&buf);
 }
 
+static void show_dates(char **argv, const char *format)
+{
+	struct date_mode mode;
+
+	parse_date_format(format, &mode);
+	for (; *argv; argv++) {
+		char *arg = *argv;
+		time_t t;
+		int tz;
+
+		/*
+		 * Do not use our normal timestamp parsing here, as the point
+		 * is to test the formatting code in isolation.
+		 */
+		t = strtol(arg, &arg, 10);
+		while (*arg == ' ')
+			arg++;
+		tz = atoi(arg);
+
+		printf("%s -> %s\n", *argv, show_date(t, tz, &mode));
+	}
+}
+
 static void parse_dates(char **argv, struct timeval *now)
 {
 	struct strbuf result = STRBUF_INIT;
@@ -63,6 +87,8 @@ int main(int argc, char **argv)
 		usage(usage_msg);
 	if (!strcmp(*argv, "relative"))
 		show_relative_dates(argv+1, &now);
+	else if (skip_prefix(*argv, "show:", &x))
+		show_dates(argv+1, x);
 	else if (!strcmp(*argv, "parse"))
 		parse_dates(argv+1, &now);
 	else if (!strcmp(*argv, "approxidate"))
diff --git a/t/t0006-date.sh b/t/t0006-date.sh
index fa05269..57033dd 100755
--- a/t/t0006-date.sh
+++ b/t/t0006-date.sh
@@ -27,6 +27,27 @@ check_relative 630000000 '20 years ago'
 check_relative 31449600 '12 months ago'
 check_relative 62985600 '2 years ago'
 
+check_show () {
+	format=$1
+	time=$2
+	expect=$3
+	test_expect_${4:-success} "show date ($format:$time)" '
+		echo "$time -> $expect" >expect &&
+		test-date show:$format "$time" >actual &&
+		test_cmp expect actual
+	'
+}
+
+# arbitrary but sensible time for examples
+TIME='1466000000 +0200'
+check_show iso8601 "$TIME" '2016-06-15 16:13:20 +0200'
+check_show iso8601-strict "$TIME" '2016-06-15T16:13:20+02:00'
+check_show rfc2822 "$TIME" 'Wed, 15 Jun 2016 16:13:20 +0200'
+check_show short "$TIME" '2016-06-15'
+check_show default "$TIME" 'Wed Jun 15 16:13:20 2016 +0200'
+check_show raw "$TIME" '1466000000 +0200'
+check_show iso-local "$TIME" '2016-06-15 14:13:20 +0000'
+
 check_parse() {
 	echo "$1 -> $2" >expect
 	test_expect_${4:-success} "parse date ($1${3:+ TZ=$3})" "
-- 
2.9.0.167.g9e4667c