diff --git a/src/test/libslic3r/test_trianglemesh.cpp b/src/test/libslic3r/test_trianglemesh.cpp
index 35dced1fb..023d06553 100644
--- a/src/test/libslic3r/test_trianglemesh.cpp
+++ b/src/test/libslic3r/test_trianglemesh.cpp
@@ -7,6 +7,7 @@
 #include <algorithm>
 
 using namespace Slic3r;
+using namespace std;
 
 SCENARIO( "TriangleMesh: Basic mesh statistics") {
     GIVEN( "A 20mm cube, built from constexpr std::array" ) {