tests: add signature checks

[gnulib.git] / tests / test-isnan.c

diff --git a/tests/test-isnan.c b/tests/test-isnan.c
index e9dd5e3..74bb9d9 100644 (file)
--- a/tests/test-isnan.c
+++ b/tests/test-isnan.c
@@ -21,6 +21,11 @@
 
 #include <math.h>
 
+/* isnan must be a macro.  */
+#ifndef isnan
+# error missing declaration
+#endif
+
 #include <float.h>
 #include <limits.h>
 #include <stdio.h>