add ErrataConnector::get_filter() helper method

- helper method to implement general filter query pattern
- add support for release/product difference in nesting filter
  parameters
- support for paginated requests
- basic unittest for filter helper based on usage

Works with the following

et.get_filter('/api/v1/releases', 'filter', is_active="true",
	  enabled="true", name='OpenStack 14.0.z for RHEL 7')

works with the following
et.get_filter('/errata', 'errata_filter[filter_params]',
	  show_type_RHBA=1, show_type_RHEA=1, show_type_RHSA=1,
	  show_state_NEW_FILES=1, show_state_QE=1,
          show_state_REL_PREP=1,show_state_PUSH_READY=1,
          open_closed_option='exclude', release=856)

Note: errata endpoint releases and products have to be special
handled to include extra [] and multiple entries if you want them

Related: red-hat-storage#132

errata_tool/connector.py

@@ -310,3 +310,37 @@ def get_paginated_data(self, api_url):
             if page_number >= PAGE_LIMIT:
                 raise RuntimeError('hit pagination timeout: %d' % page_number)
         return data
+
+    def get_filter(self, endpoint, filter_arg, **kwargs):
+        """format and generate filter get request
+
+        expose a general filter helper method to format kwargs up
+        as parameters for ET filter request.  Then return generated
+        json object
+        """
+
+        if endpoint is None or filter_arg is None:
+            return None
+
+        url = endpoint + "?"
+        param_list = []
+        keys = list(kwargs)
+        keys.sort()
+        for k in keys:
+            v = kwargs[k]
+            if k in ('paginated'):
+                continue
+            if k in ('release', 'product'):
+                param_list.append("{0}[{1}][]={2}".format(filter_arg, k, v))
+            else:
+                param_list.append("{0}[{1}]={2}".format(filter_arg, k, v))
+        print(param_list)
+        url = url + "&".join(param_list)
+        if endpoint == '/errata':
+            url = url + '&format=json'
+        print(url)
+
+        if 'paginated' in kwargs and kwargs['paginated']:
+            return {'data': self.get_paginated_data(url)}
+
+        return self._get(url)

errata_tool/tests/conftest.py

@@ -76,6 +76,14 @@ def mock_put():
     return RequestRecorder()
 
 
+@pytest.fixture
+def sample_connector(monkeypatch, mock_get):
+    monkeypatch.delattr('requests.sessions.Session.request')
+    monkeypatch.setattr(ErrataConnector, '_auth', None)
+    monkeypatch.setattr(ErrataConnector, '_username', 'test')
+    monkeypatch.setattr(requests, 'get', mock_get)
+    return ErrataConnector()
+
 @pytest.fixture
 def advisory(monkeypatch, mock_get):
     monkeypatch.delattr('requests.sessions.Session.request')

errata_tool/tests/test_filter.py

@@ -0,0 +1,33 @@
+import requests
+
+
+class TestFilter(object):
+
+    def test_filter_none(self, sample_connector):
+        assert sample_connector.get_filter(None, None) is None
+
+    def test_filter_sample(self, sample_connector):
+        assert sample_connector.get_filter(
+            '/api/v1/releases', 'filter', name='rhceph-3.1')
+
+    def test_filter_sample_check_url(self, monkeypatch, mock_get,
+                                     sample_connector):
+        monkeypatch.setattr(requests, 'get', mock_get)
+        assert sample_connector.get_filter(
+            '/api/v1/releases', 'filter', name='rhceph-3.1')
+        assert 'page' not in mock_get.response.url
+
+    def test_filter_url_paginated_false(self, monkeypatch,
+                                        mock_get, sample_connector):
+        monkeypatch.setattr(requests, 'get', mock_get)
+        assert sample_connector.get_filter(
+            '/api/v1/releases', 'filter', name='rhceph-3.1', paginated=False)
+        assert 'page' not in mock_get.response.url
+
+    def test_filter_sample_check_url_paginated(self, monkeypatch, mock_get,
+                                               sample_connector):
+        monkeypatch.setattr(requests, 'get', mock_get)
+        assert sample_connector.get_filter(
+            '/api/v1/external_tests/', 'filter', errata_id='33840',
+            test_type='rpmdiff', active='true', paginated=True)
+        assert 'page' in mock_get.response.url