Fix compiler warning in test code
diff --git a/test/qcbor_decode_tests.c b/test/qcbor_decode_tests.c
index e0d8202..755d032 100644
--- a/test/qcbor_decode_tests.c
+++ b/test/qcbor_decode_tests.c
@@ -6072,7 +6072,7 @@
 
    uCBORError = QCBORDecode_Finish(&DCtx);
 
-   return uCBORError;
+   return (int32_t)uCBORError;
 }
 
 #endif /* QCBOR_DISABLE_INDEFINITE_LENGTH_STRINGS */