Add a failing test: whether futurize invokes old_div() when __future__.division is already imported.

It shouldn't be ;)

Author: edschofield

future/tests/test_futurize.py

@@ -517,9 +517,6 @@ def test_literal_prefixes_are_not_stripped(self):
         self.unchanged(code)
 
     def test_division(self):
-        """
-        TODO: implement this!
-        """
         before = """
         x = 1 / 2
         """
@@ -529,6 +526,16 @@ def test_division(self):
         """
         self.convert_check(before, after, stages=[1, 2])
 
+    def test_already_future_division(self):
+        code = """
+        from __future__ import division
+        x = 1 / 2
+        assert x == 0.5
+        y = 3. / 2.
+        assert y == 1.5
+        """
+        self.unchanged(code)
+
 
 class TestFuturizeRenamedStdlib(CodeHandler):
     @unittest.skip('Infinite loop?')