Add cloudfoundry config values

also added tests

tests/app/test_template_previews.py

@@ -0,0 +1,35 @@
+from unittest.mock import Mock
+from notifications_utils.template import LetterPreviewTemplate
+
+from app.template_previews import TemplatePreview
+
+
+def test_from_utils_template_calls_through(mocker, mock_get_service_letter_template):
+    mock_from_db = mocker.patch('app.template_previews.TemplatePreview.from_database_object')
+    template = LetterPreviewTemplate(mock_get_service_letter_template(None, None)['data'])
+
+    ret = TemplatePreview.from_utils_template(template, 'foo')
+
+    assert ret == mock_from_db.return_value
+    mock_from_db.assert_called_once_with(template._template, 'foo', template.values)
+
+
+def test_from_database_object_makes_request(mocker, client):
+    resp = Mock(content='a', status_code='b', headers={'c': 'd'})
+    request_mock = mocker.patch('app.template_previews.requests.post', return_value=resp)
+    mocker.patch('app.template_previews.current_service', __getitem__=Mock(return_value='123'))
+
+    ret = TemplatePreview.from_database_object(template='foo', filetype='bar')
+
+    assert ret[0] == 'a'
+    assert ret[1] == 'b'
+    assert list(ret[2]) == [('c', 'd')]
+    url = 'http://localhost:6013/preview.bar'
+    data = {
+        'letter_contact_block': '123',
+        'template': 'foo',
+        'values': None
+    }
+    headers = {'Authorization': 'Token my-secret-key'}
+
+    request_mock.assert_called_once_with(url, json=data, headers=headers)