diff --git a/tests/io/CancelFutureTest.cpp b/tests/io/CancelFutureTest.cpp
index 46ac6eb0a682a0fa0592190f981e6ca120a868b9..4776d6c4788578447074bb1554a41f1ddcffec9a 100644
--- a/tests/io/CancelFutureTest.cpp
+++ b/tests/io/CancelFutureTest.cpp
@@ -5,6 +5,7 @@
 #include <cerrno>		// for ECANCELED, ETIME
 #include <cstdint>	// for uint64_t, int32_t
 #include <memory>
+#include <ostream>
 
 #include "Common.hpp"
 #include "CountingPrivateSemaphore.hpp"
@@ -26,7 +27,9 @@ uint64_t write_buf = 42;
 
 static void cancelSubmittedCallback() {
 	ReadFuture readFuture(efd, &read_buf, sizeof(read_buf), 0);
-	readFuture.setCallback([](int32_t res) { ASSERT(res == -ECANCELED) });
+	readFuture.setCallback([](int32_t res) {
+		ASSERT_MSG(res == -ECANCELED, "Expected res == -ECANCELED, got " << res);
+	});
 	readFuture.submit();
 	int32_t res = readFuture.cancel();