[PATCH BlueZ v1 4/8] unit/test-util: Add str2utf8 tests

[Luiz Augusto von Dentz <luiz.dentz@gmail.com>]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Cover the cases str2utf8() is meant to handle: well-formed input that
has to be left alone, whitespace stripping, input that is not NUL
terminated, and the ill-formed sequences that have to be replaced,
including the overlong encodings, the UTF-16 surrogates and the code
points past U+10FFFF.

Also check that a maximal subpart is replaced by a single U+FFFD rather
than one per byte, and that the result is always well-formed UTF-8.

Assisted-by: Claude:claude-opus-5
---
 unit/test-util.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)

diff --git a/unit/test-util.c b/unit/test-util.c
index 1672b32eb39c..f0b1bb7994fb 100644
--- a/unit/test-util.c
+++ b/unit/test-util.c
@@ -83,6 +83,85 @@ static void test_min_max(const void *data)
 	tester_test_passed();
 }
 
+struct str2utf8_data {
+	const char *input;	/* Not NUL terminated, len bytes are used */
+	size_t len;
+	const char *expected;
+};
+
+#define FFFD "\xef\xbf\xbd"		/* U+FFFD REPLACEMENT CHARACTER */
+
+static const struct str2utf8_data str2utf8_tests[] = {
+	/* Nothing to do */
+	{ "", 0, "" },
+	{ "Pixel 7", 7, "Pixel 7" },
+	/* Well-formed multi-byte sequences are kept as they are */
+	{ "\xe2\x82\xac 5", 5, "\xe2\x82\xac 5" },		/* U+20AC */
+	{ "\xf0\x9f\x94\x8a", 4, "\xf0\x9f\x94\x8a" },		/* U+1F50A */
+	/* Leading and trailing whitespace is removed */
+	{ "  spaced  ", 10, "spaced" },
+	{ "\t\r\nname\n\r\t", 10, "name" },
+	{ "   ", 3, "" },
+	/* The name is not NUL terminated, only len bytes are used */
+	{ "truncated", 4, "trun" },
+	/* A byte that can never appear in UTF-8 */
+	{ "ab\xff""cd", 5, "ab" FFFD "cd" },
+	/* A continuation byte cannot start a sequence */
+	{ "ab\x80""cd", 5, "ab" FFFD "cd" },
+	/* One U+FFFD per maximal subpart, not per byte */
+	{ "ab\xe2\x82""cd", 6, "ab" FFFD "cd" },
+	/* A sequence cut short by len is still one maximal subpart */
+	{ "ab\xe2\x82\xac", 4, "ab" FFFD },
+	/* Latin-1 text is not valid UTF-8 */
+	{ "caf\xe9", 4, "caf" FFFD },
+	/* Overlong encodings are rejected, C0 and C1 are never valid */
+	{ "\xc0\x80", 2, FFFD FFFD },
+	{ "\xc0\xaf", 2, FFFD FFFD },
+	/* UTF-16 surrogates have no UTF-8 encoding */
+	{ "\xed\xa0\x80", 3, FFFD FFFD FFFD },
+	/* U+10FFFF is the last code point, F5 to FF are out of range */
+	{ "\xf4\x90\x80\x80", 4, FFFD FFFD FFFD FFFD },
+	{ "\xf5\x80\x80\x80", 4, FFFD FFFD FFFD FFFD },
+	/* The last code point itself is fine */
+	{ "\xf4\x8f\xbf\xbf", 4, "\xf4\x8f\xbf\xbf" },
+	/* Replacement and stripping combined */
+	{ " \xff ", 3, FFFD },
+};
+
+static void test_str2utf8(const void *data)
+{
+	size_t i;
+
+	for (i = 0; i < sizeof(str2utf8_tests) /
+				sizeof(str2utf8_tests[0]); i++) {
+		const struct str2utf8_data *test = &str2utf8_tests[i];
+		char *str = str2utf8((const uint8_t *) test->input,
+								test->len);
+
+		assert(str);
+		if (strcmp(str, test->expected)) {
+			printf("test %zu: expected \"%s\", got \"%s\"\n", i,
+							test->expected, str);
+			free(str);
+			tester_test_failed();
+			return;
+		}
+
+		/* The result is always well-formed UTF-8 */
+		assert(strisutf8(str, strlen(str)));
+
+		free(str);
+	}
+
+	tester_test_passed();
+}
+
+static void test_str2utf8_null(const void *data)
+{
+	assert(!str2utf8(NULL, 0));
+	tester_test_passed();
+}
+
 int main(int argc, char *argv[])
 {
 	tester_init(&argc, &argv);
@@ -95,6 +174,10 @@ int main(int argc, char *argv[])
 			test_cleanup_type, NULL);
 	tester_add("/util/cleanup_fd", NULL, NULL,
 			test_cleanup_fd, NULL);
+	tester_add("/util/str2utf8", NULL, NULL,
+			test_str2utf8, NULL);
+	tester_add("/util/str2utf8_null", NULL, NULL,
+			test_str2utf8_null, NULL);
 
 	return tester_run();
 }
-- 
2.54.0