Add tests on error being thrown registering duplicate classes

Author: YannickJadoul

tests/test_class.cpp

@@ -444,6 +444,28 @@ TEST_SUBMODULE(class_, m) {
         .def_static("get_name", []() { return "BaseWithNested::Nested"; });
     py::class_<DerivedWithNested::Nested>(derivedWithNested_class, "Nested")
         .def_static("get_name", []() { return "DerivedWithNested::Nested"; });
+
+    // test_register_duplicate_class
+    struct Duplicate {};
+    struct OtherDuplicate {};
+    struct DuplicateNested {};
+    struct OtherDuplicateNested {};
+    m.def("register_duplicate_class_name", [](py::module_ m) {
+        py::class_<Duplicate>(m, "Duplicate");
+        py::class_<OtherDuplicate>(m, "Duplicate");
+    });
+    m.def("register_duplicate_class_type", [](py::module_ m) {
+        py::class_<OtherDuplicate>(m, "OtherDuplicate");
+        py::class_<OtherDuplicate>(m, "YetAnotherDuplicate");
+    });
+    m.def("register_duplicate_nested_class_name", [](py::object gt) {
+        py::class_<DuplicateNested>(gt, "DuplicateNested");
+        py::class_<OtherDuplicateNested>(gt, "DuplicateNested");
+    });
+    m.def("register_duplicate_nested_class_type", [](py::object gt) {
+        py::class_<OtherDuplicateNested>(gt, "OtherDuplicateNested");
+        py::class_<OtherDuplicateNested>(gt, "YetAnotherDuplicateNested");
+    });
 }
 
 template <int N> class BreaksBase { public:

tests/test_class.py

@@ -391,3 +391,29 @@ def test_base_and_derived_nested_scope():
     assert m.BaseWithNested.Nested != m.DerivedWithNested.Nested
     assert m.BaseWithNested.Nested.get_name() == "BaseWithNested::Nested"
     assert m.DerivedWithNested.Nested.get_name() == "DerivedWithNested::Nested"
+
+
+def test_register_duplicate_class():
+    import types
+    module_scope = types.ModuleType("module_scope")
+    with pytest.raises(RuntimeError) as exc_info:
+        m.register_duplicate_class_name(module_scope)
+    expected = ('generic_type: cannot initialize type "Duplicate": '
+                'an object with that name is already defined')
+    assert str(exc_info.value) == expected
+    with pytest.raises(RuntimeError) as exc_info:
+        m.register_duplicate_class_type(module_scope)
+    expected = 'generic_type: type "YetAnotherDuplicate" is already registered!'
+    assert str(exc_info.value) == expected
+
+    class ClassScope:
+        pass
+    with pytest.raises(RuntimeError) as exc_info:
+        m.register_duplicate_nested_class_name(ClassScope)
+    expected = ('generic_type: cannot initialize type "DuplicateNested": '
+                'an object with that name is already defined')
+    assert str(exc_info.value) == expected
+    with pytest.raises(RuntimeError) as exc_info:
+        m.register_duplicate_nested_class_type(ClassScope)
+    expected = 'generic_type: type "YetAnotherDuplicateNested" is already registered!'
+    assert str(exc_info.value) == expected