Implement Python slicing support for QByteArray

PySide2 for Python 3 didn't support get item by slice, e.g.
```
>>> from PySide2.QtCore import QByteArray
>>> ba = QByteArray('1234567890')
>>> ba[2:4]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: sequence index must be integer, not 'slice'
```
This is because get item by slice is supported by mp_subscript.
But current PySide2 doesn't implemented it. So I added __mgetitem__ in
QByteArray. And we also need to keep __getitem__ to support iterate over
QByteArray.
Also removed the __getslice__ from QByteArray.

Task-number: PYSIDE-567
Change-Id: I01f79cc2ab8700da92155cfad96be2e98bb8b331
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

1 files changed, 13 insertions, 8 deletions

diff --git a/sources/pyside2/tests/QtCore/qbytearray_test.py b/sources/pyside2/tests/QtCore/qbytearray_test.py
index c6008cf12..0be972c0a 100644
--- a/sources/pyside2/tests/QtCore/qbytearray_test.py
+++ b/sources/pyside2/tests/QtCore/qbytearray_test.py
@@ -152,15 +152,20 @@ class QByteArrayOnQVariant(unittest.TestCase):
         a = QSettings().value("some_prop", QByteArray())
         self.assertEqual(type(a), QByteArray)
 
-class TestBug666(unittest.TestCase):
-    '''QByteArray does not support slices'''
+class TestBug567(unittest.TestCase):
+    '''
+    QByteArray should support slices
+    '''
     def testIt(self):
-        if not py3k.IS_PY3K:
-            ba = QByteArray('1234567890')
-            self.assertEqual(ba[2:4], '34')
-            self.assertEqual(ba[:4], '1234')
-            self.assertEqual(ba[4:], '567890')
-            self.assertEqual(len(ba[4:1]), 0)
+        ba = QByteArray('1234567890')
+        self.assertEqual(ba[2:4], '34')
+        self.assertEqual(ba[:4], '1234')
+        self.assertEqual(ba[4:], '567890')
+        self.assertEqual(len(ba[4:1]), 0)
+        self.assertEqual(ba[::-1], '0987654321')
+        self.assertEqual(ba[::2], '13579')
+        self.assertEqual(ba[::-2], '08642')
+        self.assertEqual(ba[2:8:3], '36')
 
 class QByteArrayBug514(unittest.TestCase):
     def testIt(self):