1 files changed, 1 insertions, 1 deletions

diff --git a/test/test.h b/test/test.h
index e753977..615402b 100644
--- a/test/test.h
+++ b/test/test.h
@@ -26,7 +26,7 @@ bool isconsistent(cube_t);
 bool issolvable(cube_t);
 bool issolved(cube_t);
 cube_t readcube(char *, char *);
-int64_t writecube(char *, cube_t, size_t n, char [n]);
+int64_t writecube(const char *, cube_t, size_t n, char [n]);
 
 /* Test function to be implemented by all tests */
 void run(void);