diff --git a/tests/unistd_test.cpp b/tests/unistd_test.cpp
index f7a5afd..9969d49 100644
--- a/tests/unistd_test.cpp
+++ b/tests/unistd_test.cpp
@@ -18,6 +18,7 @@
 #include "ScopedSignalHandler.h"
 #include "TemporaryFile.h"
 
+#include <errno.h>
 #include <fcntl.h>
 #include <stdint.h>
 #include <unistd.h>