[PATCH 1/1] test: test truncation in snprintf()

[Heinrich Schuchardt]

Test that the return value of snprintf() is correct in the case of
truncation.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
---
 test/print_ut.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/test/print_ut.c b/test/print_ut.c
index 152a8c3334..7b2e7bb152 100644
--- a/test/print_ut.c
+++ b/test/print_ut.c
@@ -31,6 +31,7 @@ static int print_guid(struct unit_test_state *uts)
 		1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16
 	};
 	char str[40];
+	int ret;
 
 	sprintf(str, "%pUb", guid);
 	ut_assertok(strcmp("01020304-0506-0708-090a-0b0c0d0e0f10", str));
@@ -40,6 +41,9 @@ static int print_guid(struct unit_test_state *uts)
 	ut_assertok(strcmp("04030201-0605-0807-090a-0b0c0d0e0f10", str));
 	sprintf(str, "%pUL", guid);
 	ut_assertok(strcmp("04030201-0605-0807-090A-0B0C0D0E0F10", str));
+	ret = snprintf(str, 4, "%pUL", guid);
+	ut_asserteq(0, str[3]);
+	ut_asserteq(36, ret);
 
 	return 0;
 }
@@ -349,6 +353,20 @@ static int print_itoa(struct unit_test_state *uts)
 }
 PRINT_TEST(print_itoa, 0);
 
+static int snprint(struct unit_test_state *uts)
+{
+	char buf[10] = "xxxxxxxxx";
+	int ret;
+
+	ret = snprintf(buf, 4, "%s:%s", "abc", "def");
+	ut_asserteq(0, buf[3]);
+	ut_asserteq(7, ret);
+	ret = snprintf(buf, 4, "%s:%d", "abc", 9999);
+	ut_asserteq(8, ret);
+	return 0;
+}
+PRINT_TEST(snprint, 0);
+
 static int print_xtoa(struct unit_test_state *uts)
 {
 	ut_asserteq_str("7f", simple_xtoa(127));
-- 
2.32.0