[3.14] pythongh-131357: Add tests for zero-sized bytes objects in test_bytes.py (pythonGH-134234) (python#134378)

pythongh-131357: Add tests for zero-sized bytes objects in test_bytes.py (pythonGH-134234)
(cherry picked from commit 306f9e0)

Co-authored-by: abstractedfox <[email protected]>
Co-authored-by: Victor Stinner <[email protected]>

Author: 3 people

Lib/test/test_capi/test_bytes.py

@@ -22,6 +22,7 @@ def test_check(self):
         # Test PyBytes_Check()
         check = _testlimitedcapi.bytes_check
         self.assertTrue(check(b'abc'))
+        self.assertTrue(check(b''))
         self.assertFalse(check('abc'))
         self.assertFalse(check(bytearray(b'abc')))
         self.assertTrue(check(BytesSubclass(b'abc')))
@@ -36,6 +37,7 @@ def test_checkexact(self):
         # Test PyBytes_CheckExact()
         check = _testlimitedcapi.bytes_checkexact
         self.assertTrue(check(b'abc'))
+        self.assertTrue(check(b''))
         self.assertFalse(check('abc'))
         self.assertFalse(check(bytearray(b'abc')))
         self.assertFalse(check(BytesSubclass(b'abc')))
@@ -108,6 +110,7 @@ def test_asstring(self):
 
         self.assertEqual(asstring(b'abc', 4), b'abc\0')
         self.assertEqual(asstring(b'abc\0def', 8), b'abc\0def\0')
+        self.assertEqual(asstring(b'', 1), b'\0')
         self.assertRaises(TypeError, asstring, 'abc', 0)
         self.assertRaises(TypeError, asstring, object(), 0)
 
@@ -120,6 +123,7 @@ def test_asstringandsize(self):
 
         self.assertEqual(asstringandsize(b'abc', 4), (b'abc\0', 3))
         self.assertEqual(asstringandsize(b'abc\0def', 8), (b'abc\0def\0', 7))
+        self.assertEqual(asstringandsize(b'', 1), (b'\0', 0))
         self.assertEqual(asstringandsize_null(b'abc', 4), b'abc\0')
         self.assertRaises(ValueError, asstringandsize_null, b'abc\0def', 8)
         self.assertRaises(TypeError, asstringandsize, 'abc', 0)
@@ -163,6 +167,7 @@ def test_concat(self, concat=None):
         self.assertEqual(concat(b'', bytearray(b'def')), b'def')
         self.assertEqual(concat(memoryview(b'xabcy')[1:4], b'def'), b'abcdef')
         self.assertEqual(concat(b'abc', memoryview(b'xdefy')[1:4]), b'abcdef')
+        self.assertEqual(concat(b'', b''), b'')
 
         self.assertEqual(concat(b'abc', b'def', True), b'abcdef')
         self.assertEqual(concat(b'abc', bytearray(b'def'), True), b'abcdef')