diff --git a/tests/input/evdev/TestHelpers.h b/tests/input/evdev/TestHelpers.h
index 461db04..d26adfb 100644
--- a/tests/input/evdev/TestHelpers.h
+++ b/tests/input/evdev/TestHelpers.h
@@ -42,7 +42,7 @@
  */
 class TempFile {
 public:
-    TempFile(const char* path);
+    explicit TempFile(const char* path);
     ~TempFile();
 
     // No copy or assign