Avoid unused-variable warnings in some configurations
diff --git a/tests/suites/test_suite_pk.function b/tests/suites/test_suite_pk.function
index fac7e61..231a74d 100644
--- a/tests/suites/test_suite_pk.function
+++ b/tests/suites/test_suite_pk.function
@@ -207,6 +207,9 @@
     mbedtls_md_type_t valid_md = MBEDTLS_MD_SHA256;
     void *options = buf;
 
+    (void) null_buf;
+    (void) p;
+
     mbedtls_pk_init( &pk );
 
     TEST_INVALID_PARAM( mbedtls_pk_init( NULL ) );