newbytes: accept empty sequences like [] and return newbytes(b'')

edschofield · edschofield · commit 45c97da34ec5 · 2014-04-12T22:51:02.000+10:00
- Also add a test that would have failed before
diff --git a/future/builtins/types/newbytes.py b/future/builtins/types/newbytes.py
@@ -86,16 +86,18 @@ def __new__(cls, *args, **kwargs):
             ### 
         elif isinstance(args[0], Iterable):
             if len(args[0]) == 0:
-                # What is this?
-                raise ValueError('unknown argument type')
-            # Was: elif len(args[0]) > 0 and isinstance(args[0][0], Integral):
-            #      # It's a list of integers
-            # But then we can't index into e.g. frozensets. Try to proceed anyway.
-            try:
-                values = [chr(x) for x in args[0]]
-                value = b''.join(values)
-            except:
-                raise ValueError('bytes must be in range(0, 256)')
+                # This could be an empty list or tuple. Return b'' as on Py3.
+                value = b''
+            else:
+                # Was: elif len(args[0])>0 and isinstance(args[0][0], Integral):
+                #      # It's a list of integers
+                # But then we can't index into e.g. frozensets. Try to proceed
+                # anyway.
+                try:
+                    values = [chr(x) for x in args[0]]
+                    value = b''.join(values)
+                except:
+                    raise ValueError('bytes must be in range(0, 256)')
         elif isinstance(args[0], Integral):
             if args[0] < 0:
                 raise ValueError('negative count')
diff --git a/future/tests/test_bytes.py b/future/tests/test_bytes.py
@@ -472,6 +472,23 @@ def test_bytes_hasattr_encode(self):
         self.assertFalse(hasattr(b, 'encode'))
         self.assertTrue(hasattr(b, 'decode'))
 
+    def test_quote_from_bytes(self):
+        """
+        This test was failing in the backported urllib.parse module in quote_from_bytes
+        """
+        empty = bytes([])
+        self.assertEqual(empty, b'')
+        self.assertTrue(type(empty), bytes)
+
+        empty2 = bytes(())
+        self.assertEqual(empty2, b'')
+        self.assertTrue(type(empty2), bytes)
+
+        safe = bytes(u'Philosopher guy: 孔子. More text here.'.encode('utf-8'))
+        safe = bytes([c for c in safe if c < 128])
+        self.assertEqual(safe, b'Philosopher guy: . More text here.')
+        self.assertTrue(type(safe), bytes)
+
 
 if __name__ == '__main__':
     unittest.main()
