diff --git a/test/test_sha1.cpp b/test/test_sha1.cpp
index c8a509d..100e4ac 100644
--- a/test/test_sha1.cpp
+++ b/test/test_sha1.cpp
@@ -13,6 +13,7 @@
 #elif defined(__GNUC__)
 #  pragma GCC diagnostic push
 #  pragma GCC diagnostic ignored "-Wconversion"
+#  pragma GCC diagnostic ignored "-Wsign-conversion"
 #  pragma GCC diagnostic ignored "-Wold-style-cast"
 #endif