Add CppDrvd2, test_PPPCCC (needs more work).

Author: rwgk

tests/test_python_multiple_inheritance.cpp

@@ -26,6 +26,18 @@ struct CppDrvd : CppBase {
     int drvd_value;
 };
 
+struct CppDrvd2 : CppBase {
+    explicit CppDrvd2(int value) : CppBase(value), drvd2_value(value * 5) {}
+    int get_drvd2_value() const { return drvd2_value; }
+    void reset_drvd2_value(int new_value) { drvd2_value = new_value; }
+
+    int get_base_value_from_drvd2() const { return get_base_value(); }
+    void reset_base_value_from_drvd2(int new_value) { reset_base_value(new_value); }
+
+private:
+    int drvd2_value;
+};
+
 } // namespace test_python_multiple_inheritance
 
 TEST_SUBMODULE(python_multiple_inheritance, m) {
@@ -42,4 +54,11 @@ TEST_SUBMODULE(python_multiple_inheritance, m) {
         .def("reset_drvd_value", &CppDrvd::reset_drvd_value)
         .def("get_base_value_from_drvd", &CppDrvd::get_base_value_from_drvd)
         .def("reset_base_value_from_drvd", &CppDrvd::reset_base_value_from_drvd);
+
+    py::class_<CppDrvd2, CppBase>(m, "CppDrvd2")
+        .def(py::init<int>())
+        .def("get_drvd2_value", &CppDrvd2::get_drvd2_value)
+        .def("reset_drvd2_value", &CppDrvd2::reset_drvd2_value)
+        .def("get_base_value_from_drvd2", &CppDrvd2::get_base_value_from_drvd2)
+        .def("reset_base_value_from_drvd2", &CppDrvd2::reset_base_value_from_drvd2);
 }

tests/test_python_multiple_inheritance.py

@@ -1,6 +1,8 @@
 # Adapted from:
 # https://github.com/google/clif/blob/5718e4d0807fd3b6a8187dde140069120b81ecef/clif/testing/python/python_multiple_inheritance_test.py
 
+import pytest
+
 from pybind11_tests import python_multiple_inheritance as m
 
 
@@ -12,6 +14,10 @@ class PPCC(PC, m.CppDrvd):
     pass
 
 
+class PPPCCC(PPCC, m.CppDrvd2):
+    pass
+
+
 def test_PC():
     d = PC(11)
     assert d.get_base_value() == 11
@@ -33,3 +39,11 @@ def test_PPCC():
     d.reset_base_value_from_drvd(30)
     assert d.get_base_value() == 30
     assert d.get_base_value_from_drvd() == 30
+
+
+def test_PPPCCC():
+    with pytest.raises(
+        TypeError,
+        match=r"CppDrvd2\.__init__\(\) must be called when overriding __init__$",
+    ):
+        PPPCCC(11)