diff --git a/test/infcover.c b/test/infcover.c
index 2be0164..8912c40 100644
--- a/test/infcover.c
+++ b/test/infcover.c
@@ -373,7 +373,7 @@
     mem_setup(&strm);
     strm.avail_in = 0;
     strm.next_in = Z_NULL;
-    ret = inflateInit_(&strm, ZLIB_VERSION - 1, (int)sizeof(z_stream));
+    ret = inflateInit_(&strm, "!", (int)sizeof(z_stream));
                                                 assert(ret == Z_VERSION_ERROR);
     mem_done(&strm, "wrong version");
 
@@ -462,7 +462,8 @@
 
 local int push(void *desc, unsigned char *buf, unsigned len)
 {
-    buf += len;
+    (void)buf;
+    (void)len;
     return desc != Z_NULL;      /* force error if desc not null */
 }