Have fix_open subclass fix_file

That guarantees that any open-related scenario is fixed.

Closes #74

Author: brettcannon

libmodernize/fixes/fix_open.py

@@ -1,18 +1,19 @@
+from libmodernize.fixes import fix_file
 from lib2to3 import fixer_base
 from lib2to3.fixer_util import touch_import
 
 
-class FixOpen(fixer_base.ConditionalFix):
+class FixOpen(fix_file.FixFile):
 
     BM_compatible = True
     order = "pre"
-    skip_on = "io.open"
 
     PATTERN = """
-    power< 'open' trailer< '(' any+ ')' > >
+    power< name=('open'|'file') trailer< '(' any+ ')' > any* >
     """
 
     def transform(self, node, results):
-        if self.should_skip(node):
-            return
         touch_import(u'io', u'open', node)
+        if len(results['name']) == 1 and results['name'][0].value == 'file':
+            results['name'] = results['name'][0]
+            super(FixOpen, self).transform(node, results)

tests/test_fix_open.py

@@ -8,9 +8,19 @@
 open('some/path')
 """)
 
+FILE = ("""\
+file('some/path')
+""", """\
+from io import open
+open('some/path')
+""")
+
 
 def test_open():
     check_on_input(*OPEN, extra_flags=['-f', 'libmodernize.fixes.fix_open'])
 
 def test_open_optional():
     check_on_input(OPEN[0], OPEN[0])
+
+def test_file():
+    check_on_input(*FILE, extra_flags=['-f', 'libmodernize.fixes.fix_open'])