Add more tests

Author: sidhant007

Lib/test/test_csv.py

@@ -231,12 +231,17 @@ def test_writerows_with_none(self):
             self.assertEqual(fileobj.read(), 'a\r\n""\r\n')
 
     def test_writerows_with_bytes(self):
-        with TemporaryFile("w+", newline='', encoding='iso-8859-1') as fileobj:
+        with TemporaryFile("w+", newline='', encoding='latin-1') as fileobj:
             writer = csv.writer(fileobj)
             writer.writerows([['a', b'\xc2'], [b'\xc2', 'c']])
             fileobj.seek(0);
             self.assertEqual(fileobj.read(), 'a,\xc2\r\n\xc2,c\r\n')
 
+        with TemporaryFile("w+", newline='', encoding='utf-8') as fileobj:
+            writer = csv.writer(fileobj)
+            self.assertRaises(UnicodeDecodeError, writer.writerows, [['a', b'\xc2'], ['a', 'c']])
+
+
     @support.cpython_only
     def test_writerows_legacy_strings(self):
         import _testcapi