style: clang-tidy: modernize-use-auto
diff --git a/tests/test_numpy_array.cpp b/tests/test_numpy_array.cpp
index caa0525..33f1d78 100644
--- a/tests/test_numpy_array.cpp
+++ b/tests/test_numpy_array.cpp
@@ -212,7 +212,7 @@
         .def(py::init<>())
         .def("numpy_view", [](py::object &obj) {
             py::print("ArrayClass::numpy_view()");
-            ArrayClass &a = obj.cast<ArrayClass&>();
+            auto &a = obj.cast<ArrayClass&>();
             return py::array_t<int>({2}, {4}, a.data, obj);
         }
     );
@@ -362,7 +362,7 @@
     // test_array_resize
     // reshape array to 2D without changing size
     sm.def("array_reshape2", [](py::array_t<double> a) {
-        const ssize_t dim_sz = (ssize_t)std::sqrt(a.size());
+        const auto dim_sz = (ssize_t)std::sqrt(a.size());
         if (dim_sz * dim_sz != a.size())
             throw std::domain_error("array_reshape2: input array total size is not a squared integer");
         a.resize({dim_sz, dim_sz});