increased test coverage

lib/wf/timer/test/wf/timer/test_timer.cc

@@ -37,8 +37,7 @@ TEST(wf_timer, trigger)
     struct wf_timer_manager * manager = wf_timer_manager_create();
     struct wf_timer * timer = wf_timer_create(manager, &on_timeout, reinterpret_cast<void*>(&triggered));
 
-    wf_timer_start(timer, 250);
-    std::this_thread::sleep_for(500ms);
+    wf_timer_start(timer, -1);
     wf_timer_manager_check(manager);
 
     ASSERT_TRUE(triggered);
@@ -135,3 +134,15 @@ TEST(wf_timer, multiple_timers)
 
     wf_timer_manager_dispose(manager);
 }
+
+TEST(wf_timer, dont_trigger_null_callback)
+{
+    struct wf_timer_manager * manager = wf_timer_manager_create();
+    struct wf_timer * timer = wf_timer_create(manager, nullptr, nullptr);
+    
+    wf_timer_start(timer, -1);
+    wf_timer_manager_check(manager);
+
+    wf_timer_dispose(timer);
+    wf_timer_manager_dispose(manager);
+}