test: add litest string comparison macros

Part-of: <https://gitlab.freedesktop.org/libinput/libinput/-/merge_requests/1059>

test/litest-selftest.c

@@ -420,6 +420,38 @@ START_TEST(litest_double_ge_fails)
 }
 END_TEST
 
+START_TEST(litest_string_eq_ne)
+{
+	litest_assert_str_eq("foo", "foo");
+	litest_assert_str_ne("foo", "bar");
+	litest_assert_str_ne("foo", "foobar");
+	litest_assert_str_ne("foobar", "foo");
+
+	const char *a1 = "a";
+	const char *a2 = "a";
+	const char *b = "b";
+
+	litest_assert_str_eq(NULL, NULL);
+	litest_assert_str_eq(a1, a2);
+	litest_assert_str_ne(a1, b);
+	litest_assert_str_ne(a2, b);
+	litest_assert_str_ne(a2, b);
+	litest_assert_str_ne(b, NULL);
+}
+END_TEST
+
+START_TEST(litest_string_eq_fails)
+{
+	litest_assert_str_eq("foo", "bar");
+}
+END_TEST
+
+START_TEST(litest_string_ne_fails)
+{
+	litest_assert_str_ne("foo", "foo");
+}
+END_TEST
+
 START_TEST(zalloc_overflow)
 {
 	zalloc((size_t)-1);
@@ -514,6 +546,12 @@ litest_assert_macros_suite(void)
 	tcase_add_test_raise_signal(tc, litest_double_ge_fails, SIGABRT);
 	suite_add_tcase(s, tc);
 
+	tc = tcase_create("string comparison ");
+	tcase_add_test(tc, litest_string_eq_ne);
+	tcase_add_test_raise_signal(tc, litest_string_eq_fails, SIGABRT);
+	tcase_add_test_raise_signal(tc, litest_string_ne_fails, SIGABRT);
+	suite_add_tcase(s, tc);
+
 	tc = tcase_create("zalloc ");
 	tcase_add_test(tc, zalloc_max_size);
 	tcase_add_test_raise_signal(tc, zalloc_overflow, SIGABRT);

test/litest.c

@@ -258,6 +258,23 @@ litest_fail_comparison_ptr(const char *file,
 	abort();
 }
 
+__attribute__((noreturn))
+void
+litest_fail_comparison_str(const char *file,
+			   int line,
+			   const char *func,
+			   const char *comparison,
+			   const char *operator,
+			   const char *astr,
+			   const char *bstr)
+{
+	litest_log("FAILED COMPARISON: %s %s %s\n", astr, operator, bstr);
+	litest_log("Resolved to: %s %s %s\n", astr, operator, bstr);
+	litest_log("in %s() (%s:%d)\n", func, file, line);
+	litest_backtrace();
+	abort();
+}
+
 struct test {
 	struct list node;
 	char *name;

test/litest.h

@@ -131,6 +131,15 @@ litest_fail_comparison_ptr(const char *file,
 			   const char *func,
 			   const char *comparison);
 
+void
+litest_fail_comparison_str(const char *file,
+			   int line,
+			   const char *func,
+			   const char *comparison,
+			   const char *operator,
+			   const char *astr,
+			   const char *bstr);
+
 #define litest_assert(cond) \
 	do { \
 		if (!(cond)) \
@@ -222,6 +231,28 @@ litest_fail_comparison_ptr(const char *file,
 #define litest_assert_ptr_notnull(a_) \
 	litest_assert_comparison_ptr_(a_, !=, NULL)
 
+#define litest_assert_str_eq(a_, b_) \
+	do { \
+		const char *_a = a_; \
+		const char *_b = b_; \
+		if (!streq(_a, _b)) \
+			litest_fail_comparison_str(__FILE__, __LINE__, __func__,\
+						   #a_ " == " #b_, \
+						   "==", \
+						   _a, _b); \
+	} while(0)
+
+#define litest_assert_str_ne(a_, b_) \
+	do { \
+		const char *_a = a_; \
+		const char *_b = b_; \
+		if (streq(_a, _b)) \
+			litest_fail_comparison_str(__FILE__, __LINE__, __func__,\
+						   #a_ " != " #b_, \
+						   "!=", \
+						   _a, _b); \
+	} while(0)
+
 #define LITEST_DEFAULT_EPSILON  0.001
 
 #define litest_assert_double_eq_epsilon(a_, b_, epsilon_)\