Only install cheetah (and only run the cheetah templating test) when in Python

2.  Cheetah is not compatible with Python 3.

requirements.txt

@@ -1,7 +1,6 @@
 # Pypi requirements for cloud-init to work
 
 # Used for untemplating any files or strings with parameters.
-cheetah
 jinja2
 
 # This is used for any pretty printing of tabular data.
@@ -32,3 +31,6 @@ requests
 
 # For patching pieces of cloud-config together
 jsonpatch
+
+# For Python 2/3 compatibility
+six

setup.py

@@ -175,6 +175,11 @@ else:
     }
 
 
+requirements = read_requires()
+if sys.version_info < (3,):
+    requirements.append('cheetah')
+
+
 setuptools.setup(name='cloud-init',
       version=get_version(),
       description='EC2 initialisation magic',
@@ -187,6 +192,6 @@ setuptools.setup(name='cloud-init',
                ],
       license='GPLv3',
       data_files=data_files,
-      install_requires=read_requires(),
+      install_requires=requirements,
       cmdclass=cmdclass,
       )

tests/unittests/test_templating.py

@@ -16,6 +16,9 @@
 #    You should have received a copy of the GNU General Public License
 #    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+import six
+import unittest
+
 from . import helpers as test_helpers
 import textwrap
 
@@ -38,6 +41,7 @@ class TestTemplates(test_helpers.TestCase):
         out_data = templater.basic_render(in_data, {'b': 2})
         self.assertEqual(expected_data.strip(), out_data)
 
+    @unittest.skipIf(six.PY3, 'Cheetah is not compatible with Python 3')
     def test_detection(self):
         blob = "## template:cheetah"