Move tests from short translation units into their logical parents

docs/advanced/classes.rst

@@ -325,7 +325,7 @@ ensuring member initialization and (eventual) destruction.
 
 .. seealso::
 
-    See the file :file:`tests/test_alias_initialization.cpp` for complete examples
+    See the file :file:`tests/test_virtual_functions.cpp` for complete examples
     showing both normal and forced trampoline instantiation.
 
 .. _custom_constructors:

tests/CMakeLists.txt

@@ -26,7 +26,6 @@ endif()
 
 # Full set of test files (you can override these; see below)
 set(PYBIND11_TEST_FILES
-  test_alias_initialization.cpp
   test_buffers.cpp
   test_builtin_casters.cpp
   test_call_policies.cpp
@@ -40,7 +39,6 @@ set(PYBIND11_TEST_FILES
   test_enum.cpp
   test_eval.cpp
   test_exceptions.cpp
-  test_inheritance.cpp
   test_kwargs_and_defaults.cpp
   test_methods_and_attributes.cpp
   test_modules.cpp

tests/test_alias_initialization.cpp

@@ -1,62 +0,0 @@
-/*
-    tests/test_alias_initialization.cpp -- test cases and example of different trampoline
-    initialization modes
-
-    Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>, Jason Rhinelander <jason@imaginary.ca>
-
-    All rights reserved. Use of this source code is governed by a
-    BSD-style license that can be found in the LICENSE file.
-*/
-
-#include "pybind11_tests.h"
-
-test_initializer alias_initialization([](py::module &m) {
-    // don't invoke Python dispatch classes by default when instantiating C++ classes that were not
-    // extended on the Python side
-    struct A {
-        virtual ~A() {}
-        virtual void f() { py::print("A.f()"); }
-    };
-
-    struct PyA : A {
-        PyA() { py::print("PyA.PyA()"); }
-        ~PyA() { py::print("PyA.~PyA()"); }
-
-        void f() override {
-            py::print("PyA.f()");
-            PYBIND11_OVERLOAD(void, A, f);
-        }
-    };
-
-    auto call_f = [](A *a) { a->f(); };
-
-    py::class_<A, PyA>(m, "A")
-        .def(py::init<>())
-        .def("f", &A::f);
-
-    m.def("call_f", call_f);
-
-
-    // ... unless we explicitly request it, as in this example:
-    struct A2 {
-        virtual ~A2() {}
-        virtual void f() { py::print("A2.f()"); }
-    };
-
-    struct PyA2 : A2 {
-        PyA2() { py::print("PyA2.PyA2()"); }
-        ~PyA2() { py::print("PyA2.~PyA2()"); }
-        void f() override {
-            py::print("PyA2.f()");
-            PYBIND11_OVERLOAD(void, A2, f);
-        }
-    };
-
-    py::class_<A2, PyA2>(m, "A2")
-        .def(py::init_alias<>())
-        .def("f", &A2::f);
-
-    m.def("call_f", [](A2 *a2) { a2->f(); });
-
-});
-

tests/test_alias_initialization.py

@@ -1,80 +0,0 @@
-import pytest
-
-
-def test_alias_delay_initialization1(capture):
-    """
-    A only initializes its trampoline class when we inherit from it; if we just
-    create and use an A instance directly, the trampoline initialization is
-    bypassed and we only initialize an A() instead (for performance reasons).
-    """
-    from pybind11_tests import A, call_f
-
-    class B(A):
-        def __init__(self):
-            super(B, self).__init__()
-
-        def f(self):
-            print("In python f()")
-
-    # C++ version
-    with capture:
-        a = A()
-        call_f(a)
-        del a
-        pytest.gc_collect()
-    assert capture == "A.f()"
-
-    # Python version
-    with capture:
-        b = B()
-        call_f(b)
-        del b
-        pytest.gc_collect()
-    assert capture == """
-        PyA.PyA()
-        PyA.f()
-        In python f()
-        PyA.~PyA()
-    """
-
-
-def test_alias_delay_initialization2(capture):
-    """A2, unlike the above, is configured to always initialize the alias; while
-    the extra initialization and extra class layer has small virtual dispatch
-    performance penalty, it also allows us to do more things with the trampoline
-    class such as defining local variables and performing construction/destruction.
-    """
-    from pybind11_tests import A2, call_f
-
-    class B2(A2):
-        def __init__(self):
-            super(B2, self).__init__()
-
-        def f(self):
-            print("In python B2.f()")
-
-    # No python subclass version
-    with capture:
-        a2 = A2()
-        call_f(a2)
-        del a2
-        pytest.gc_collect()
-    assert capture == """
-        PyA2.PyA2()
-        PyA2.f()
-        A2.f()
-        PyA2.~PyA2()
-    """
-
-    # Python subclass version
-    with capture:
-        b2 = B2()
-        call_f(b2)
-        del b2
-        pytest.gc_collect()
-    assert capture == """
-        PyA2.PyA2()
-        PyA2.f()
-        In python B2.f()
-        PyA2.~PyA2()
-    """

tests/test_class.cpp

@@ -23,6 +23,133 @@ TEST_SUBMODULE(class_, m) {
 
     py::class_<NoConstructor>(m, "NoConstructor")
         .def_static("new_instance", &NoConstructor::new_instance, "Return an instance");
+
+    // test_inheritance
+    class Pet {
+    public:
+        Pet(const std::string &name, const std::string &species)
+            : m_name(name), m_species(species) {}
+        std::string name() const { return m_name; }
+        std::string species() const { return m_species; }
+    private:
+        std::string m_name;
+        std::string m_species;
+    };
+
+    class Dog : public Pet {
+    public:
+        Dog(const std::string &name) : Pet(name, "dog") {}
+        std::string bark() const { return "Woof!"; }
+    };
+
+    class Rabbit : public Pet {
+    public:
+        Rabbit(const std::string &name) : Pet(name, "parrot") {}
+    };
+
+    class Hamster : public Pet {
+    public:
+        Hamster(const std::string &name) : Pet(name, "rodent") {}
+    };
+
+    class Chimera : public Pet {
+        Chimera() : Pet("Kimmy", "chimera") {}
+    };
+
+    py::class_<Pet> pet_class(m, "Pet");
+    pet_class
+        .def(py::init<std::string, std::string>())
+        .def("name", &Pet::name)
+        .def("species", &Pet::species);
+
+    /* One way of declaring a subclass relationship: reference parent's class_ object */
+    py::class_<Dog>(m, "Dog", pet_class)
+        .def(py::init<std::string>());
+
+    /* Another way of declaring a subclass relationship: reference parent's C++ type */
+    py::class_<Rabbit, Pet>(m, "Rabbit")
+        .def(py::init<std::string>());
+
+    /* And another: list parent in class template arguments */
+    py::class_<Hamster, Pet>(m, "Hamster")
+        .def(py::init<std::string>());
+
+    /* Constructors are not inherited by default */
+    py::class_<Chimera, Pet>(m, "Chimera");
+
+    m.def("pet_name_species", [](const Pet &pet) { return pet.name() + " is a " + pet.species(); });
+    m.def("dog_bark", [](const Dog &dog) { return dog.bark(); });
+
+    // test_automatic_upcasting
+    struct BaseClass { virtual ~BaseClass() {} };
+    struct DerivedClass1 : BaseClass { };
+    struct DerivedClass2 : BaseClass { };
+
+    py::class_<BaseClass>(m, "BaseClass").def(py::init<>());
+    py::class_<DerivedClass1>(m, "DerivedClass1").def(py::init<>());
+    py::class_<DerivedClass2>(m, "DerivedClass2").def(py::init<>());
+
+    m.def("return_class_1", []() -> BaseClass* { return new DerivedClass1(); });
+    m.def("return_class_2", []() -> BaseClass* { return new DerivedClass2(); });
+    m.def("return_class_n", [](int n) -> BaseClass* {
+        if (n == 1) return new DerivedClass1();
+        if (n == 2) return new DerivedClass2();
+        return new BaseClass();
+    });
+    m.def("return_none", []() -> BaseClass* { return nullptr; });
+
+    // test_isinstance
+    m.def("check_instances", [](py::list l) {
+        return py::make_tuple(
+            py::isinstance<py::tuple>(l[0]),
+            py::isinstance<py::dict>(l[1]),
+            py::isinstance<Pet>(l[2]),
+            py::isinstance<Pet>(l[3]),
+            py::isinstance<Dog>(l[4]),
+            py::isinstance<Rabbit>(l[5]),
+            py::isinstance<UnregisteredType>(l[6])
+        );
+    });
+
+    // test_mismatched_holder
+    struct MismatchBase1 { };
+    struct MismatchDerived1 : MismatchBase1 { };
+
+    struct MismatchBase2 { };
+    struct MismatchDerived2 : MismatchBase2 { };
+
+    m.def("mismatched_holder_1", []() {
+        auto mod = py::module::import("__main__");
+        py::class_<MismatchBase1, std::shared_ptr<MismatchBase1>>(mod, "MismatchBase1");
+        py::class_<MismatchDerived1, MismatchBase1>(mod, "MismatchDerived1");
+    });
+    m.def("mismatched_holder_2", []() {
+        auto mod = py::module::import("__main__");
+        py::class_<MismatchBase2>(mod, "MismatchBase2");
+        py::class_<MismatchDerived2, std::shared_ptr<MismatchDerived2>,
+                   MismatchBase2>(mod, "MismatchDerived2");
+    });
+
+    // test_override_static
+    // #511: problem with inheritance + overwritten def_static
+    struct MyBase {
+        static std::unique_ptr<MyBase> make() {
+            return std::unique_ptr<MyBase>(new MyBase());
+        }
+    };
+
+    struct MyDerived : MyBase {
+        static std::unique_ptr<MyDerived> make() {
+            return std::unique_ptr<MyDerived>(new MyDerived());
+        }
+    };
+
+    py::class_<MyBase>(m, "MyBase")
+        .def_static("make", &MyBase::make);
+
+    py::class_<MyDerived, MyBase>(m, "MyDerived")
+        .def_static("make", &MyDerived::make)
+        .def_static("make2", &MyDerived::make);
 }
 
 template <int N> class BreaksBase {};

tests/test_class.py

@@ -42,3 +42,80 @@ def test_docstrings(doc):
 
         Return an instance
     """
+
+
+def test_inheritance(msg):
+    roger = m.Rabbit('Rabbit')
+    assert roger.name() + " is a " + roger.species() == "Rabbit is a parrot"
+    assert m.pet_name_species(roger) == "Rabbit is a parrot"
+
+    polly = m.Pet('Polly', 'parrot')
+    assert polly.name() + " is a " + polly.species() == "Polly is a parrot"
+    assert m.pet_name_species(polly) == "Polly is a parrot"
+
+    molly = m.Dog('Molly')
+    assert molly.name() + " is a " + molly.species() == "Molly is a dog"
+    assert m.pet_name_species(molly) == "Molly is a dog"
+
+    fred = m.Hamster('Fred')
+    assert fred.name() + " is a " + fred.species() == "Fred is a rodent"
+
+    assert m.dog_bark(molly) == "Woof!"
+
+    with pytest.raises(TypeError) as excinfo:
+        m.dog_bark(polly)
+    assert msg(excinfo.value) == """
+        dog_bark(): incompatible function arguments. The following argument types are supported:
+            1. (arg0: m.class_.Dog) -> str
+
+        Invoked with: <m.class_.Pet object at 0>
+    """
+
+    with pytest.raises(TypeError) as excinfo:
+        m.Chimera("lion", "goat")
+    assert "No constructor defined!" in str(excinfo.value)
+
+
+def test_automatic_upcasting():
+    assert type(m.return_class_1()).__name__ == "DerivedClass1"
+    assert type(m.return_class_2()).__name__ == "DerivedClass2"
+    assert type(m.return_none()).__name__ == "NoneType"
+    # Repeat these a few times in a random order to ensure no invalid caching is applied
+    assert type(m.return_class_n(1)).__name__ == "DerivedClass1"
+    assert type(m.return_class_n(2)).__name__ == "DerivedClass2"
+    assert type(m.return_class_n(0)).__name__ == "BaseClass"
+    assert type(m.return_class_n(2)).__name__ == "DerivedClass2"
+    assert type(m.return_class_n(2)).__name__ == "DerivedClass2"
+    assert type(m.return_class_n(0)).__name__ == "BaseClass"
+    assert type(m.return_class_n(1)).__name__ == "DerivedClass1"
+
+
+def test_isinstance():
+    objects = [tuple(), dict(), m.Pet("Polly", "parrot")] + [m.Dog("Molly")] * 4
+    expected = (True, True, True, True, True, False, False)
+    assert m.check_instances(objects) == expected
+
+
+def test_mismatched_holder():
+    import re
+
+    with pytest.raises(RuntimeError) as excinfo:
+        m.mismatched_holder_1()
+    assert re.match('generic_type: type ".*MismatchDerived1" does not have a non-default '
+                    'holder type while its base ".*MismatchBase1" does', str(excinfo.value))
+
+    with pytest.raises(RuntimeError) as excinfo:
+        m.mismatched_holder_2()
+    assert re.match('generic_type: type ".*MismatchDerived2" has a non-default holder type '
+                    'while its base ".*MismatchBase2" does not', str(excinfo.value))
+
+
+def test_override_static():
+    """#511: problem with inheritance + overwritten def_static"""
+    b = m.MyBase.make()
+    d1 = m.MyDerived.make2()
+    d2 = m.MyDerived.make()
+
+    assert isinstance(b, m.MyBase)
+    assert isinstance(d1, m.MyDerived)
+    assert isinstance(d2, m.MyDerived)

tests/test_inheritance.cpp

@@ -1,141 +0,0 @@
-/*
-    tests/test_inheritance.cpp -- inheritance, automatic upcasting for polymorphic types
-
-    Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>
-
-    All rights reserved. Use of this source code is governed by a
-    BSD-style license that can be found in the LICENSE file.
-*/
-
-#include "pybind11_tests.h"
-
-class Pet {
-public:
-    Pet(const std::string &name, const std::string &species)
-        : m_name(name), m_species(species) {}
-    std::string name() const { return m_name; }
-    std::string species() const { return m_species; }
-private:
-    std::string m_name;
-    std::string m_species;
-};
-
-class Dog : public Pet {
-public:
-    Dog(const std::string &name) : Pet(name, "dog") {}
-    std::string bark() const { return "Woof!"; }
-};
-
-class Rabbit : public Pet {
-public:
-    Rabbit(const std::string &name) : Pet(name, "parrot") {}
-};
-
-class Hamster : public Pet {
-public:
-    Hamster(const std::string &name) : Pet(name, "rodent") {}
-};
-
-class Chimera : public Pet {
-    Chimera() : Pet("Kimmy", "chimera") {}
-};
-
-std::string pet_name_species(const Pet &pet) {
-    return pet.name() + " is a " + pet.species();
-}
-
-std::string dog_bark(const Dog &dog) {
-    return dog.bark();
-}
-
-
-struct BaseClass { virtual ~BaseClass() {} };
-struct DerivedClass1 : BaseClass { };
-struct DerivedClass2 : BaseClass { };
-
-struct MismatchBase1 { };
-struct MismatchDerived1 : MismatchBase1 { };
-
-struct MismatchBase2 { };
-struct MismatchDerived2 : MismatchBase2 { };
-
-test_initializer inheritance([](py::module &m) {
-    py::class_<Pet> pet_class(m, "Pet");
-    pet_class
-        .def(py::init<std::string, std::string>())
-        .def("name", &Pet::name)
-        .def("species", &Pet::species);
-
-    /* One way of declaring a subclass relationship: reference parent's class_ object */
-    py::class_<Dog>(m, "Dog", pet_class)
-        .def(py::init<std::string>());
-
-    /* Another way of declaring a subclass relationship: reference parent's C++ type */
-    py::class_<Rabbit, Pet>(m, "Rabbit")
-        .def(py::init<std::string>());
-
-    /* And another: list parent in class template arguments */
-    py::class_<Hamster, Pet>(m, "Hamster")
-        .def(py::init<std::string>());
-
-    py::class_<Chimera, Pet>(m, "Chimera");
-
-    m.def("pet_name_species", pet_name_species);
-    m.def("dog_bark", dog_bark);
-
-    py::class_<BaseClass>(m, "BaseClass").def(py::init<>());
-    py::class_<DerivedClass1>(m, "DerivedClass1").def(py::init<>());
-    py::class_<DerivedClass2>(m, "DerivedClass2").def(py::init<>());
-
-    m.def("return_class_1", []() -> BaseClass* { return new DerivedClass1(); });
-    m.def("return_class_2", []() -> BaseClass* { return new DerivedClass2(); });
-    m.def("return_class_n", [](int n) -> BaseClass* {
-        if (n == 1) return new DerivedClass1();
-        if (n == 2) return new DerivedClass2();
-        return new BaseClass();
-    });
-    m.def("return_none", []() -> BaseClass* { return nullptr; });
-
-    m.def("test_isinstance", [](py::list l) {
-        return py::make_tuple(
-            py::isinstance<py::tuple>(l[0]),
-            py::isinstance<py::dict>(l[1]),
-            py::isinstance<Pet>(l[2]),
-            py::isinstance<Pet>(l[3]),
-            py::isinstance<Dog>(l[4]),
-            py::isinstance<Rabbit>(l[5]),
-            py::isinstance<UnregisteredType>(l[6])
-        );
-    });
-
-    m.def("test_mismatched_holder_type_1", []() {
-        auto m = py::module::import("__main__");
-        py::class_<MismatchBase1, std::shared_ptr<MismatchBase1>>(m, "MismatchBase1");
-        py::class_<MismatchDerived1, MismatchBase1>(m, "MismatchDerived1");
-    });
-    m.def("test_mismatched_holder_type_2", []() {
-        auto m = py::module::import("__main__");
-        py::class_<MismatchBase2>(m, "MismatchBase2");
-        py::class_<MismatchDerived2, std::shared_ptr<MismatchDerived2>, MismatchBase2>(m, "MismatchDerived2");
-    });
-
-    // #511: problem with inheritance + overwritten def_static
-    struct MyBase {
-        static std::unique_ptr<MyBase> make() {
-            return std::unique_ptr<MyBase>(new MyBase());
-        }
-    };
-
-    struct MyDerived : MyBase {
-        static std::unique_ptr<MyDerived> make() {
-            return std::unique_ptr<MyDerived>(new MyDerived());
-        }
-    };
-
-    py::class_<MyBase>(m, "MyBase")
-        .def_static("make", &MyBase::make);
-
-    py::class_<MyDerived, MyBase>(m, "MyDerived")
-        .def_static("make", &MyDerived::make)
-        .def_static("make2", &MyDerived::make);
-});

tests/test_inheritance.py

@@ -1,91 +0,0 @@
-import pytest
-
-
-def test_inheritance(msg):
-    from pybind11_tests import Pet, Dog, Rabbit, Hamster, Chimera, dog_bark, pet_name_species
-
-    roger = Rabbit('Rabbit')
-    assert roger.name() + " is a " + roger.species() == "Rabbit is a parrot"
-    assert pet_name_species(roger) == "Rabbit is a parrot"
-
-    polly = Pet('Polly', 'parrot')
-    assert polly.name() + " is a " + polly.species() == "Polly is a parrot"
-    assert pet_name_species(polly) == "Polly is a parrot"
-
-    molly = Dog('Molly')
-    assert molly.name() + " is a " + molly.species() == "Molly is a dog"
-    assert pet_name_species(molly) == "Molly is a dog"
-
-    fred = Hamster('Fred')
-    assert fred.name() + " is a " + fred.species() == "Fred is a rodent"
-
-    assert dog_bark(molly) == "Woof!"
-
-    with pytest.raises(TypeError) as excinfo:
-        dog_bark(polly)
-    assert msg(excinfo.value) == """
-        dog_bark(): incompatible function arguments. The following argument types are supported:
-            1. (arg0: m.Dog) -> str
-
-        Invoked with: <m.Pet object at 0>
-    """
-
-    with pytest.raises(TypeError) as excinfo:
-        Chimera("lion", "goat")
-    assert "No constructor defined!" in str(excinfo.value)
-
-
-def test_automatic_upcasting():
-    from pybind11_tests import return_class_1, return_class_2, return_class_n, return_none
-
-    assert type(return_class_1()).__name__ == "DerivedClass1"
-    assert type(return_class_2()).__name__ == "DerivedClass2"
-    assert type(return_none()).__name__ == "NoneType"
-    # Repeat these a few times in a random order to ensure no invalid caching
-    # is applied
-    assert type(return_class_n(1)).__name__ == "DerivedClass1"
-    assert type(return_class_n(2)).__name__ == "DerivedClass2"
-    assert type(return_class_n(0)).__name__ == "BaseClass"
-    assert type(return_class_n(2)).__name__ == "DerivedClass2"
-    assert type(return_class_n(2)).__name__ == "DerivedClass2"
-    assert type(return_class_n(0)).__name__ == "BaseClass"
-    assert type(return_class_n(1)).__name__ == "DerivedClass1"
-
-
-def test_isinstance():
-    from pybind11_tests import test_isinstance, Pet, Dog
-
-    objects = [tuple(), dict(), Pet("Polly", "parrot")] + [Dog("Molly")] * 4
-    expected = (True, True, True, True, True, False, False)
-    assert test_isinstance(objects) == expected
-
-
-def test_holder():
-    from pybind11_tests import test_mismatched_holder_type_1, test_mismatched_holder_type_2
-
-    with pytest.raises(RuntimeError) as excinfo:
-        test_mismatched_holder_type_1()
-
-    assert str(excinfo.value) == ("generic_type: type \"MismatchDerived1\" does not have "
-                                  "a non-default holder type while its base "
-                                  "\"MismatchBase1\" does")
-
-    with pytest.raises(RuntimeError) as excinfo:
-        test_mismatched_holder_type_2()
-
-    assert str(excinfo.value) == ("generic_type: type \"MismatchDerived2\" has a "
-                                  "non-default holder type while its base "
-                                  "\"MismatchBase2\" does not")
-
-
-def test_inheritance_override_def_static():
-    """#511: problem with inheritance + overwritten def_static"""
-    from pybind11_tests import MyBase, MyDerived
-
-    b = MyBase.make()
-    d1 = MyDerived.make2()
-    d2 = MyDerived.make()
-
-    assert isinstance(b, MyBase)
-    assert isinstance(d1, MyDerived)
-    assert isinstance(d2, MyDerived)

tests/test_virtual_functions.cpp

@@ -322,7 +322,7 @@ struct DispatchIssue : Base {
     }
 };
 
-test_initializer virtual_functions([](py::module &m) {
+TEST_SUBMODULE(virtual_functions, m) {
     py::class_<ExampleVirt, PyExampleVirt>(m, "ExampleVirt")
         .def(py::init<int>())
         /* Reference original class in function definitions */
@@ -352,6 +352,52 @@ test_initializer virtual_functions([](py::module &m) {
     m.def("cstats_debug", &ConstructorStats::get<ExampleVirt>);
     initialize_inherited_virtuals(m);
 
+    // test_alias_delay_initialization1
+    // don't invoke Python dispatch classes by default when instantiating C++ classes
+    // that were not extended on the Python side
+    struct A {
+        virtual ~A() {}
+        virtual void f() { py::print("A.f()"); }
+    };
+
+    struct PyA : A {
+        PyA() { py::print("PyA.PyA()"); }
+        ~PyA() { py::print("PyA.~PyA()"); }
+
+        void f() override {
+            py::print("PyA.f()");
+            PYBIND11_OVERLOAD(void, A, f);
+        }
+    };
+
+    py::class_<A, PyA>(m, "A")
+        .def(py::init<>())
+        .def("f", &A::f);
+
+    m.def("call_f", [](A *a) { a->f(); });
+
+    // test_alias_delay_initialization2
+    // ... unless we explicitly request it, as in this example:
+    struct A2 {
+        virtual ~A2() {}
+        virtual void f() { py::print("A2.f()"); }
+    };
+
+    struct PyA2 : A2 {
+        PyA2() { py::print("PyA2.PyA2()"); }
+        ~PyA2() { py::print("PyA2.~PyA2()"); }
+        void f() override {
+            py::print("PyA2.f()");
+            PYBIND11_OVERLOAD(void, A2, f);
+        }
+    };
+
+    py::class_<A2, PyA2>(m, "A2")
+        .def(py::init_alias<>())
+        .def("f", &A2::f);
+
+    m.def("call_f", [](A2 *a2) { a2->f(); });
+
     // #159: virtual function dispatch has problems with similar-named functions
     py::class_<Base, DispatchIssue>(m, "DispatchIssue")
         .def(py::init<>())
@@ -398,4 +444,4 @@ test_initializer virtual_functions([](py::module &m) {
 //      .def("str_ref", &OverrideTest::str_ref)
         .def("A_value", &OverrideTest::A_value)
         .def("A_ref", &OverrideTest::A_ref);
-});
+}

tests/test_virtual_functions.py

@@ -1,13 +1,11 @@
 import pytest
-import pybind11_tests
+
+from pybind11_tests import virtual_functions as m
 from pybind11_tests import ConstructorStats
 
 
 def test_override(capture, msg):
-    from pybind11_tests import (ExampleVirt, runExampleVirt, runExampleVirtVirtual,
+    class ExtendedExampleVirt(m.ExampleVirt):
-                                runExampleVirtBool)
-
-    class ExtendedExampleVirt(ExampleVirt):
         def __init__(self, state):
             super(ExtendedExampleVirt, self).__init__(state + 1)
             self.data = "Hello world"
@@ -33,40 +31,40 @@ def test_override(capture, msg):
         def get_string2(self):
             return "override2"
 
-    ex12 = ExampleVirt(10)
+    ex12 = m.ExampleVirt(10)
     with capture:
-        assert runExampleVirt(ex12, 20) == 30
+        assert m.runExampleVirt(ex12, 20) == 30
     assert capture == """
         Original implementation of ExampleVirt::run(state=10, value=20, str1=default1, str2=default2)
     """  # noqa: E501 line too long
 
     with pytest.raises(RuntimeError) as excinfo:
-        runExampleVirtVirtual(ex12)
+        m.runExampleVirtVirtual(ex12)
     assert msg(excinfo.value) == 'Tried to call pure virtual function "ExampleVirt::pure_virtual"'
 
     ex12p = ExtendedExampleVirt(10)
     with capture:
-        assert runExampleVirt(ex12p, 20) == 32
+        assert m.runExampleVirt(ex12p, 20) == 32
     assert capture == """
         ExtendedExampleVirt::run(20), calling parent..
         Original implementation of ExampleVirt::run(state=11, value=21, str1=override1, str2=default2)
     """  # noqa: E501 line too long
     with capture:
-        assert runExampleVirtBool(ex12p) is False
+        assert m.runExampleVirtBool(ex12p) is False
     assert capture == "ExtendedExampleVirt::run_bool()"
     with capture:
-        runExampleVirtVirtual(ex12p)
+        m.runExampleVirtVirtual(ex12p)
     assert capture == "ExtendedExampleVirt::pure_virtual(): Hello world"
 
     ex12p2 = ExtendedExampleVirt2(15)
     with capture:
-        assert runExampleVirt(ex12p2, 50) == 68
+        assert m.runExampleVirt(ex12p2, 50) == 68
     assert capture == """
         ExtendedExampleVirt::run(50), calling parent..
         Original implementation of ExampleVirt::run(state=17, value=51, str1=override1, str2=override2)
     """  # noqa: E501 line too long
 
-    cstats = ConstructorStats.get(ExampleVirt)
+    cstats = ConstructorStats.get(m.ExampleVirt)
     assert cstats.alive() == 3
     del ex12, ex12p, ex12p2
     assert cstats.alive() == 0
@@ -75,14 +73,88 @@ def test_override(capture, msg):
     assert cstats.move_constructions >= 0
 
 
-def test_inheriting_repeat():
+def test_alias_delay_initialization1(capture):
-    from pybind11_tests import A_Repeat, B_Repeat, C_Repeat, D_Repeat, A_Tpl, B_Tpl, C_Tpl, D_Tpl
+    """`A` only initializes its trampoline class when we inherit from it
 
-    class AR(A_Repeat):
+    If we just create and use an A instance directly, the trampoline initialization is
+    bypassed and we only initialize an A() instead (for performance reasons).
+    """
+    class B(m.A):
+        def __init__(self):
+            super(B, self).__init__()
+
+        def f(self):
+            print("In python f()")
+
+    # C++ version
+    with capture:
+        a = m.A()
+        m.call_f(a)
+        del a
+        pytest.gc_collect()
+    assert capture == "A.f()"
+
+    # Python version
+    with capture:
+        b = B()
+        m.call_f(b)
+        del b
+        pytest.gc_collect()
+    assert capture == """
+        PyA.PyA()
+        PyA.f()
+        In python f()
+        PyA.~PyA()
+    """
+
+
+def test_alias_delay_initialization2(capture):
+    """`A2`, unlike the above, is configured to always initialize the alias
+
+    While the extra initialization and extra class layer has small virtual dispatch
+    performance penalty, it also allows us to do more things with the trampoline
+    class such as defining local variables and performing construction/destruction.
+    """
+    class B2(m.A2):
+        def __init__(self):
+            super(B2, self).__init__()
+
+        def f(self):
+            print("In python B2.f()")
+
+    # No python subclass version
+    with capture:
+        a2 = m.A2()
+        m.call_f(a2)
+        del a2
+        pytest.gc_collect()
+    assert capture == """
+        PyA2.PyA2()
+        PyA2.f()
+        A2.f()
+        PyA2.~PyA2()
+    """
+
+    # Python subclass version
+    with capture:
+        b2 = B2()
+        m.call_f(b2)
+        del b2
+        pytest.gc_collect()
+    assert capture == """
+        PyA2.PyA2()
+        PyA2.f()
+        In python B2.f()
+        PyA2.~PyA2()
+    """
+
+
+def test_inheriting_repeat():
+    class AR(m.A_Repeat):
         def unlucky_number(self):
             return 99
 
-    class AT(A_Tpl):
+    class AT(m.A_Tpl):
         def unlucky_number(self):
             return 999
 
@@ -96,21 +168,21 @@ def test_inheriting_repeat():
     assert obj.unlucky_number() == 999
     assert obj.say_everything() == "hi 999"
 
-    for obj in [B_Repeat(), B_Tpl()]:
+    for obj in [m.B_Repeat(), m.B_Tpl()]:
         assert obj.say_something(3) == "B says hi 3 times"
         assert obj.unlucky_number() == 13
         assert obj.lucky_number() == 7.0
         assert obj.say_everything() == "B says hi 1 times 13"
 
-    for obj in [C_Repeat(), C_Tpl()]:
+    for obj in [m.C_Repeat(), m.C_Tpl()]:
         assert obj.say_something(3) == "B says hi 3 times"
         assert obj.unlucky_number() == 4444
         assert obj.lucky_number() == 888.0
         assert obj.say_everything() == "B says hi 1 times 4444"
 
-    class CR(C_Repeat):
+    class CR(m.C_Repeat):
         def lucky_number(self):
-            return C_Repeat.lucky_number(self) + 1.25
+            return m.C_Repeat.lucky_number(self) + 1.25
 
     obj = CR()
     assert obj.say_something(3) == "B says hi 3 times"
@@ -118,7 +190,7 @@ def test_inheriting_repeat():
     assert obj.lucky_number() == 889.25
     assert obj.say_everything() == "B says hi 1 times 4444"
 
-    class CT(C_Tpl):
+    class CT(m.C_Tpl):
         pass
 
     obj = CT()
@@ -147,14 +219,14 @@ def test_inheriting_repeat():
     assert obj.lucky_number() == 888000.0
     assert obj.say_everything() == "B says hi 1 times 4444"
 
-    class DR(D_Repeat):
+    class DR(m.D_Repeat):
         def unlucky_number(self):
             return 123
 
         def lucky_number(self):
             return 42.0
 
-    for obj in [D_Repeat(), D_Tpl()]:
+    for obj in [m.D_Repeat(), m.D_Tpl()]:
         assert obj.say_something(3) == "B says hi 3 times"
         assert obj.unlucky_number() == 4444
         assert obj.lucky_number() == 888.0
@@ -166,7 +238,7 @@ def test_inheriting_repeat():
     assert obj.lucky_number() == 42.0
     assert obj.say_everything() == "B says hi 1 times 123"
 
-    class DT(D_Tpl):
+    class DT(m.D_Tpl):
         def say_something(self, times):
             return "DT says:" + (' quack' * times)
 
@@ -189,7 +261,7 @@ def test_inheriting_repeat():
         def unlucky_number(self):
             return -3
 
-    class BT(B_Tpl):
+    class BT(m.B_Tpl):
         def say_something(self, times):
             return "BT" * times
 
@@ -209,31 +281,28 @@ def test_inheriting_repeat():
 # PyPy: Reference count > 1 causes call with noncopyable instance
 # to fail in ncv1.print_nc()
 @pytest.unsupported_on_pypy
-@pytest.mark.skipif(not hasattr(pybind11_tests, 'NCVirt'),
+@pytest.mark.skipif(not hasattr(m, "NCVirt"), reason="NCVirt test broken on ICPC")
-                    reason="NCVirt test broken on ICPC")
 def test_move_support():
-    from pybind11_tests import NCVirt, NonCopyable, Movable
+    class NCVirtExt(m.NCVirt):
-
-    class NCVirtExt(NCVirt):
         def get_noncopyable(self, a, b):
             # Constructs and returns a new instance:
-            nc = NonCopyable(a * a, b * b)
+            nc = m.NonCopyable(a * a, b * b)
             return nc
 
         def get_movable(self, a, b):
             # Return a referenced copy
-            self.movable = Movable(a, b)
+            self.movable = m.Movable(a, b)
             return self.movable
 
-    class NCVirtExt2(NCVirt):
+    class NCVirtExt2(m.NCVirt):
         def get_noncopyable(self, a, b):
             # Keep a reference: this is going to throw an exception
-            self.nc = NonCopyable(a, b)
+            self.nc = m.NonCopyable(a, b)
             return self.nc
 
         def get_movable(self, a, b):
             # Return a new instance without storing it
-            return Movable(a, b)
+            return m.Movable(a, b)
 
     ncv1 = NCVirtExt()
     assert ncv1.print_nc(2, 3) == "36"
@@ -244,8 +313,8 @@ def test_move_support():
     with pytest.raises(RuntimeError):
         ncv2.print_nc(9, 9)
 
-    nc_stats = ConstructorStats.get(NonCopyable)
+    nc_stats = ConstructorStats.get(m.NonCopyable)
-    mv_stats = ConstructorStats.get(Movable)
+    mv_stats = ConstructorStats.get(m.Movable)
     assert nc_stats.alive() == 1
     assert mv_stats.alive() == 1
     del ncv1, ncv2
@@ -261,30 +330,26 @@ def test_move_support():
 
 def test_dispatch_issue(msg):
     """#159: virtual function dispatch has problems with similar-named functions"""
-    from pybind11_tests import DispatchIssue, dispatch_issue_go
+    class PyClass1(m.DispatchIssue):
-
-    class PyClass1(DispatchIssue):
         def dispatch(self):
             return "Yay.."
 
-    class PyClass2(DispatchIssue):
+    class PyClass2(m.DispatchIssue):
         def dispatch(self):
             with pytest.raises(RuntimeError) as excinfo:
                 super(PyClass2, self).dispatch()
             assert msg(excinfo.value) == 'Tried to call pure virtual function "Base::dispatch"'
 
             p = PyClass1()
-            return dispatch_issue_go(p)
+            return m.dispatch_issue_go(p)
 
     b = PyClass2()
-    assert dispatch_issue_go(b) == "Yay.."
+    assert m.dispatch_issue_go(b) == "Yay.."
 
 
 def test_override_ref():
     """#392/397: overridding reference-returning functions"""
-    from pybind11_tests import OverrideTest
+    o = m.OverrideTest("asdf")
-
-    o = OverrideTest("asdf")
 
     # Not allowed (see associated .cpp comment)
     # i = o.str_ref()