tests: Add lib/b64_decode-test test case

Implement unit tests for lib/b64_decode module.

Signed-off-by: Anna Karas <aka@semihalf.com>
Change-Id: Id5fe9272e30eaff3d086a95241b3819101089c2b
Reviewed-on: https://review.coreboot.org/c/coreboot/+/42313
Reviewed-by: Paul Fagerburg <pfagerburg@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

tests/lib/Makefile.inc

@@ -1,6 +1,10 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
 tests-y += string-test
+tests-y += b64_decode-test
 
 string-test-srcs += tests/lib/string-test.c
 string-test-srcs += src/lib/string.c
+
+b64_decode-test-srcs += tests/lib/b64_decode-test.c
+b64_decode-test-srcs += src/lib/b64_decode.c

tests/lib/b64_decode-test.c

@@ -0,0 +1,67 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <b64_decode.h>
+#include <tests/test.h>
+
+struct messages_t {
+	const char *enc;
+	const char *dec;
+} messages[] = {
+	{"QQ==", "A"},
+	{"Q\r\nUI=", "AB"},
+	{"QUJD", "ABC"},
+	{"\nQUJDRA==", "ABCD"},
+	{"SGVsbG8\r=", "Hello"},
+	{"SGVsbG8h", "Hello!"}
+};
+
+const char *invalid[] = {
+	"QQ=-=",
+	"SGVsbG-8="
+};
+
+/* Provide necessary definition in order to satisfy dependencies. */
+int do_printk(int msg_level, const char *fmt, ...)
+{
+	return 0;
+}
+
+static void test_b64_decode(void **state)
+{
+	uint8_t *decoded;
+	size_t res;
+
+	for (int i = 0; i < ARRAY_SIZE(messages); i++) {
+		decoded = malloc(strlen(messages[i].enc) * sizeof(char));
+
+		res = b64_decode((uint8_t *)messages[i].enc, strlen(messages[i].enc), decoded);
+
+		assert_int_equal(res, (strlen(messages[i].dec)));
+		assert_string_equal(decoded, messages[i].dec);
+
+		free(decoded);
+	}
+
+	for (int i = 0; i < ARRAY_SIZE(invalid); i++) {
+		decoded = malloc(strlen(invalid[i]) * sizeof(char));
+
+		res = b64_decode((uint8_t *)invalid[i], strlen(invalid[i]), decoded);
+
+		assert_int_equal(res, 0);
+
+		free(decoded);
+	}
+}
+
+int main(void)
+{
+	const struct CMUnitTest tests[] = {
+		cmocka_unit_test(test_b64_decode),
+	};
+
+	return cmocka_run_group_tests(tests, NULL, NULL);
+}