diff --git a/src/tests/catch_test_multifluid.cxx b/src/tests/catch_test_multifluid.cxx
index 8a2ac7c365514f6231ea71fe14b77d7623855453..884b7c313592d3e94a9fd9008422073741441e11 100644
--- a/src/tests/catch_test_multifluid.cxx
+++ b/src/tests/catch_test_multifluid.cxx
@@ -412,7 +412,7 @@ TEST_CASE("Check ammonia+argon", "[multifluidArNH3]") {
 //    std::cout << mix.dump(1) << std::endl;
     CHECK(!mix.empty());
     CAPTURE(mix.dump(1));
-    CHECK(p_MPa != Approx(129.07019029846455).margin(1e-3));
+    CHECK(p_MPa == Approx(129.07019029846455).margin(1e-3));
 }