diff --git a/circle.yml b/circle.yml
index 41ae5ba..a477d80 100644
--- a/circle.yml
+++ b/circle.yml
@@ -4,4 +4,4 @@ machine:
 test:
   override:
     - bundle exec rake
-    - python setup.py test
+    - python3 setup.py test
diff --git a/metroextractor/nothingburger.py b/metroextractor/nothingburger.py
index 27a8dc0..b356bc5 100644
--- a/metroextractor/nothingburger.py
+++ b/metroextractor/nothingburger.py
@@ -1,5 +1,6 @@
 from __future__ import print_function
 from argparse import ArgumentParser
+import io
 
 parser = ArgumentParser(description='Tell us what they told you.')
 
@@ -12,7 +13,7 @@
 def tell_us(bbox, filename):
     '''
     '''
-    with open(filename, 'w') as file:
+    with io.open(filename, 'w') as file:
         print(bbox, file=file)
 
 def main():
diff --git a/metroextractor/tests.py b/metroextractor/tests.py
index 846e6dd..5686861 100644
--- a/metroextractor/tests.py
+++ b/metroextractor/tests.py
@@ -1,17 +1,13 @@
-import unittest, tempfile, os
+import unittest, unittest.mock
 
 from . import nothingburger
 
 class Nothingburger (unittest.TestCase):
 
-    def setUp(self):
-        handle, self.filename = tempfile.mkstemp()
-        os.close(handle)
-    
-    def tearDown(self):
-        os.remove(self.filename)
-
     def test_tell_us(self):
-        nothingburger.tell_us([0, 1, 2, 3], self.filename)
-        with open(self.filename) as file:
-            self.assertEqual(next(file), '[0, 1, 2, 3]\n')
\ No newline at end of file
+        with unittest.mock.patch('io.open') as io_open:
+            nothingburger.tell_us([0, 1, 2, 3], 'filename.txt')
+
+        io_open.assert_called_once_with('filename.txt', 'w')
+        write_call = io_open.return_value.__enter__.return_value.mock_calls[0]
+        self.assertTrue(write_call[1][0].startswith('[0, 1, 2, 3]'))
diff --git a/recipes/scripts.rb b/recipes/scripts.rb
index f821633..e54d7fe 100644
--- a/recipes/scripts.rb
+++ b/recipes/scripts.rb
@@ -1,4 +1,4 @@
-execute 'pip install -U .' do
+execute 'pip3 install -U .' do
   cwd File.join(File.dirname(__FILE__), '..')
   environment('LC_ALL' => 'C.UTF-8') # ...for correct encoding in python open()
 end