diff --git a/Tests/NumLib/LocalToGlobalIndexMapMultiComponent.cpp b/Tests/NumLib/LocalToGlobalIndexMapMultiComponent.cpp
index 6a96ee4a8a53e908b9391c3991d3a03e0cc5f03a..f2ac3ea8bdc994fa29ebd453edd43d4b71b8015e 100644
--- a/Tests/NumLib/LocalToGlobalIndexMapMultiComponent.cpp
+++ b/Tests/NumLib/LocalToGlobalIndexMapMultiComponent.cpp
@@ -108,7 +108,7 @@ public:
                         std::vector<int> const& selected_components,
                         NL::ComponentOrder const order)
     {
-        assert(selected_components.size() <= num_components);
+        assert(static_cast<int>(selected_components.size()) <= num_components);
 
         std::vector<MeshLib::MeshSubsets> components;
         for (int i = 0; i < num_components; ++i)