Add a few tests

dev-requirements.txt

@@ -0,0 +1,3 @@
+mock
+unittest2
+pytest

tests/test_sops.py

@@ -0,0 +1,32 @@
+import unittest2
+import mock
+
+import sops
+
+from sys import version_info
+if version_info.major == 2:
+    import __builtin__ as builtins  # pylint:disable=import-error
+else:
+    import builtins  # pylint:disable=import-error
+
+
+class TreeTest(unittest2.TestCase):
+
+    def test_json_loader_is_used_on_json_filetype(self):
+        # XXX put some real json here.
+        m = mock.mock_open(read_data='"content"')
+        with mock.patch.object(builtins, 'open', m):
+            assert sops.load_tree('path', 'json') == "content"
+
+    def test_yaml_loader_is_used_on_yaml_filetype(self):
+        # XXX put some real yaml here.
+        m = mock.mock_open(read_data='"content"')
+        with mock.patch.object(builtins, 'open', m):
+            assert sops.load_tree('path', 'yaml') == "content"
+
+    @mock.patch('sops.json.load')
+    def test_example_with_a_mocked_call(self, json_mock):
+        m = mock.mock_open(read_data='"content"')
+        with mock.patch.object(builtins, 'open', m):
+            sops.load_tree('path', 'json')
+            json_mock.assert_called_with(m())