Implement default __ne__ and __eq__ for all PySide types

PySide types have been following the Qt implementation of
comparisons, completely.

This is not correct for Python, because the Python default has
the operators `==` and `!=` at least. They are needed for tests
like `obj in collection`.

We fix this by redirecting the default case to
`PyBaseObject_Type.tp_richcompare`.
This is the correct way to fix it, because for types which do not
define `tp_richcompare', this is the default, anyway.

From the original patch, the test case is still in use.

Old message:
Implement __ne__ and __eq__ for QTreeWidgetItem

Testing if a QTreeWidgetItem belongs to a list raises a NotImplementedError.
I have exposed the operator== and the operator!= from C++ to shiboken which has solved our eq operator issue.
Implemented the test from PYSIDE-74 for the QTreeWidgetItem eq operator and the ne operator.
This also allows us to have the behavior "QTreeWidgetItem in ['a']" and "QTreeWidgetItem not in ['a']".
Adding qtreewidgetitem_test.py to CMakeFiles.txt

Fixes: PYSIDE-74
Change-Id: Id221c0163fc8c2d85730c4c26f22db5f61710706
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>

2 files changed, 75 insertions, 0 deletions

diff --git a/sources/pyside2/tests/QtWidgets/CMakeLists.txt b/sources/pyside2/tests/QtWidgets/CMakeLists.txt
index 6682136ea..28372f437 100644
--- a/sources/pyside2/tests/QtWidgets/CMakeLists.txt
+++ b/sources/pyside2/tests/QtWidgets/CMakeLists.txt
@@ -126,6 +126,7 @@ PYSIDE_TEST(qtextedit_test.py)
 PYSIDE_TEST(qtextedit_signal_test.py)
 PYSIDE_TEST(qtreeview_test.py)
 PYSIDE_TEST(qtreewidget_test.py)
+PYSIDE_TEST(qtreewidgetitem_test.py)
 PYSIDE_TEST(qtoolbar_test.py)
 PYSIDE_TEST(qtoolbox_test.py)
 PYSIDE_TEST(qvariant_test.py)
diff --git a/sources/pyside2/tests/QtWidgets/qtreewidgetitem_test.py b/sources/pyside2/tests/QtWidgets/qtreewidgetitem_test.py
new file mode 100644
index 000000000..115bce4b7
--- /dev/null
+++ b/sources/pyside2/tests/QtWidgets/qtreewidgetitem_test.py
@@ -0,0 +1,74 @@
+#!/usr/bin/python
+
+#############################################################################
+##
+## Copyright (C) 2020 The Qt Company Ltd.
+## Contact: https://www.qt.io/licensing/
+##
+## This file is part of the test suite of PySide2.
+##
+## $QT_BEGIN_LICENSE:GPL-EXCEPT$
+## Commercial License Usage
+## Licensees holding valid commercial Qt licenses may use this file in
+## accordance with the commercial license agreement provided with the
+## Software or, alternatively, in accordance with the terms contained in
+## a written agreement between you and The Qt Company. For licensing terms
+## and conditions see https://www.qt.io/terms-conditions. For further
+## information use the contact form at https://www.qt.io/contact-us.
+##
+## GNU General Public License Usage
+## Alternatively, this file may be used under the terms of the GNU
+## General Public License version 3 as published by the Free Software
+## Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+## included in the packaging of this file. Please review the following
+## information to ensure the GNU General Public License requirements will
+## be met: https://www.gnu.org/licenses/gpl-3.0.html.
+##
+## $QT_END_LICENSE$
+##
+#############################################################################
+
+"""
+Unit tests for QTreeWidgetItem
+------------------------------
+
+This test is actually meant for all types which provide `tp_richcompare`
+but actually define something without providing `==` or `!=` operators.
+QTreeWidgetItem for instance defines `<` only.
+
+PYSIDE-74: We redirect to type `object`s handling which is anyway the default
+           when `tp_richcompare` is undefined.
+"""
+
+import os
+import sys
+import unittest
+
+sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+from init_paths import init_test_paths
+init_test_paths(False)
+
+from PySide2 import QtCore, QtWidgets
+
+
+class QTreeWidgetItemTest(unittest.TestCase):
+    def testClass(self):
+        app = QtWidgets.QApplication([])
+        treewidget = QtWidgets.QTreeWidget()
+        item = QtWidgets.QTreeWidgetItem(["Words and stuff"])
+        item2 = QtWidgets.QTreeWidgetItem(["More words!"])
+        treewidget.insertTopLevelItem(0, item)
+
+        dummy_list = ["Numbers", "Symbols", "Spam"]
+        self.assertFalse(item in dummy_list)
+        self.assertTrue(item not in dummy_list)
+        self.assertFalse(item == item2)
+        self.assertTrue(item != item2)
+        treewidget.show()
+        QtCore.QTimer.singleShot(500, app.quit)
+        app.exec_()
+
+
+if __name__ == "__main__":
+    unittest.main()
+