test: test truncation in snprintf()

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

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

diff --git a/test/print_ut.c b/test/print_ut.c
index 152a8c3..7b2e7bb 100644 (file)
--- 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));