test: make assert_return() critical by default on fuzzer and unit tests

Several test cases intentionally trigger assert_return(). So, to avoid
the entire test fails, this introduces several macros that tentatively
make assert_return() not critical.

src/shared/tests.c

@@ -114,6 +114,7 @@ bool slow_tests_enabled(void) {
 }
 
 void test_setup_logging(int level) {
+        log_set_assert_return_is_critical(true);
         log_set_max_level(level);
         log_parse_environment();
         log_open();

src/shared/tests.h

@@ -10,6 +10,27 @@
 #include "static-destruct.h"
 #include "strv.h"
 
+static inline void log_set_assert_return_is_criticalp(bool *p) {
+        log_set_assert_return_is_critical(*p);
+}
+
+#define _SAVE_ASSERT_RETURN_IS_CRITICAL(b)                              \
+        _unused_ _cleanup_(log_set_assert_return_is_criticalp) bool b = \
+                log_get_assert_return_is_critical()
+
+#define SAVE_ASSERT_RETURN_IS_CRITICAL                          \
+        _SAVE_ASSERT_RETURN_IS_CRITICAL(UNIQ_T(saved, UNIQ))
+
+#define ASSERT_RETURN_IS_CRITICAL(b, expr)                              \
+        ({                                                              \
+                SAVE_ASSERT_RETURN_IS_CRITICAL;                         \
+                log_set_assert_return_is_critical(b);                   \
+                expr;                                                   \
+        })
+
+#define ASSERT_RETURN_EXPECTED(expr) ASSERT_RETURN_IS_CRITICAL(false, expr)
+#define ASSERT_RETURN_EXPECTED_SE(expr) ASSERT_RETURN_EXPECTED(assert_se(expr));
+
 static inline bool manager_errno_skip_test(int r) {
         return IN_SET(abs(r),
                       EPERM,