diff --git a/tests/syntax/libc_defs.h b/tests/syntax/libc_defs.c
similarity index 100%
rename from tests/syntax/libc_defs.h
rename to tests/syntax/libc_defs.c
diff --git a/tests/syntax/oracle/libc_defs.res.oracle b/tests/syntax/oracle/libc_defs.res.oracle
index 0705f794ef5556875f5374242963ba4c018560d6..22f21e2fa93baaff6569636a9ec0e81205883322 100644
--- a/tests/syntax/oracle/libc_defs.res.oracle
+++ b/tests/syntax/oracle/libc_defs.res.oracle
@@ -1,4 +1,4 @@
-[kernel] Parsing tests/syntax/libc_defs.h (with preprocessing)
+[kernel] Parsing tests/syntax/libc_defs.c (with preprocessing)
 /* Generated by Frama-C */
 #include "errno.c"
 #include "errno.h"