diff --git a/tests/src/test_common.h b/tests/src/test_common.h
index aaeb1e7c8..40bdd4d65 100644
--- a/tests/src/test_common.h
+++ b/tests/src/test_common.h
@@ -23,6 +23,12 @@
 #define __USE_MINGW_ANSI_STDIO 1
 #endif
 
+#if defined(__IAR_SYSTEMS_ICC__)
+/* With IAR, enable support for ::FILE functions in stdio.h.
+ */
+#define _DLIB_FILE_DESCRIPTOR 1
+#endif
+
 /* Make sure we have the library configuration, and anything else that
  * is deemed necessary in test headers. */
 #include <test/build_info.h>