Add some extra tests for empty bytearray

Author: sergey-miryanov

Lib/test/test_capi/test_bytearray.py

@@ -66,6 +66,7 @@ def test_fromobject(self):
         # Test PyByteArray_FromObject()
         fromobject = _testlimitedcapi.bytearray_fromobject
 
+        self.assertEqual(fromobject(b''), bytearray(b''))
         self.assertEqual(fromobject(b'abc'), bytearray(b'abc'))
         self.assertEqual(fromobject(bytearray(b'abc')), bytearray(b'abc'))
         self.assertEqual(fromobject(ByteArraySubclass(b'abc')), bytearray(b'abc'))
@@ -115,6 +116,7 @@ def test_concat(self):
         self.assertEqual(concat(b'abc', bytearray(b'def')), bytearray(b'abcdef'))
         self.assertEqual(concat(bytearray(b'abc'), b''), bytearray(b'abc'))
         self.assertEqual(concat(b'', bytearray(b'def')), bytearray(b'def'))
+        self.assertEqual(concat(bytearray(b''), bytearray(b'')), bytearray(b''))
         self.assertEqual(concat(memoryview(b'xabcy')[1:4], b'def'),
                          bytearray(b'abcdef'))
         self.assertEqual(concat(b'abc', memoryview(b'xdefy')[1:4]),
@@ -150,6 +152,8 @@ def test_resize(self):
         self.assertEqual(resize(ba, 0), 0)
         self.assertEqual(ba, bytearray())
 
+        self.assertEqual(resize(bytearray(b''), 0), 0)
+
         ba = ByteArraySubclass(b'abcdef')
         self.assertEqual(resize(ba, 3), 0)
         self.assertEqual(ba, bytearray(b'abc'))