diff --git a/tests/test_embed/test_interpreter.cpp b/tests/test_embed/test_interpreter.cpp
index 2d5823c..acbad6b 100644
--- a/tests/test_embed/test_interpreter.cpp
+++ b/tests/test_embed/test_interpreter.cpp
@@ -205,7 +205,7 @@
         for (auto i = 0; i < num_threads; ++i) {
             threads.emplace_back([&]() {
                 py::gil_scoped_acquire gil{};
-                py::exec("count += 1", py::globals(), locals);
+                locals["count"] = locals["count"].cast<int>() + 1;
             });
         }