diff --git a/test/source/event.cpp b/test/source/event.cpp
index 90edaec..e4d7b2a 100644
--- a/test/source/event.cpp
+++ b/test/source/event.cpp
@@ -83,6 +83,10 @@
     EXPECT_EQ(0, handler(nullptr, &defer));
     EXPECT_EQ(1, completions);
 
+    defer.set_callback(std::bind([]() {}));
+    EXPECT_EQ(0, handler(nullptr, &defer));
+    EXPECT_EQ(1, completions);
+
     expect_destruct();
 }