Add a failure test for overloaded functions

Author: otamachan

tests/test_callbacks.cpp

@@ -97,6 +97,8 @@ TEST_SUBMODULE(callbacks, m) {
     // test_cpp_function_roundtrip
     /* Test if passing a function pointer from C++ -> Python -> C++ yields the original pointer */
     m.def("dummy_function", &dummy_function);
+    m.def("dummy_function_overloaded", [](int i, int j) { return i + j; });
+    m.def("dummy_function_overloaded", &dummy_function);
     m.def("dummy_function2", [](int i, int j) { return i + j; });
     m.def("roundtrip", [](std::function<int(int)> f, bool expect_none = false) {
         if (expect_none && f)

tests/test_callbacks.py

@@ -93,6 +93,10 @@ def test_cpp_function_roundtrip():
         m.test_dummy_function(m.roundtrip(m.dummy_function))
         == "matches dummy_function: eval(1) = 2"
     )
+    assert (
+        m.test_dummy_function(m.dummy_function_overloaded)
+        == "matches dummy_function: eval(1) = 2"
+    )
     assert m.roundtrip(None, expect_none=True) is None
     assert (
         m.test_dummy_function(lambda x: x + 2)