test.py: grouped tests into 1 suit, i3.py: trivial one-line change

3 test cases are grouped into one single test suit for easier
reading of test output. One test may not pass with the current
version of i3 window manager; explanation is added.

The one-line change in i3.py is just 'list.extend' to 'list +='
in i3.filter function for increased readability.

i3.py

@@ -523,7 +523,7 @@ def filter(tree=None, function=None, **conditions):
     matches = []
     if 'nodes' in tree:
         for node in tree['nodes']:
-            matches.extend(filter(node, function, **conditions))
+            matches += filter(node, function, **conditions)
     return matches
 
 

test.py

@@ -41,6 +41,7 @@ def test_event_type_error(self):
             self.assertRaises(i3.EventTypeError, i3.parse_event_type, str(val))
 
     def test_msg_error(self):
+        """If i3.yada doesn't pass, see http://bugs.i3wm.org/report/ticket/693"""
         self.assertRaises(i3.MessageError, i3.focus)  # missing argument
         self.assertRaises(i3.MessageError, i3.yada)  # doesn't exist
         self.assertRaises(i3.MessageError, i3.meh, 'some', 'args')
@@ -117,15 +118,16 @@ def test_filter2(self):
         self.assertGreater(parent_count, 0)
 
     def test_filter_function_wikipedia(self):
-        """You have to have Wikipedia tab opened in a browser."""
-        import re
-        func = lambda node: re.search(r'Wikipedia', node['name'])
+        """You have to have a Wikipedia tab opened in a browser."""
+        func = lambda node: 'Wikipedia' in node['name']
         nodes = i3.filter(function=func)
         self.assertTrue(nodes != [])
         for node in nodes:
             self.assertTrue('free encyclopedia' in node['name'])
 
 if __name__ == '__main__':
+    test_suits = []
     for Test in [ParseTest, SocketTest, GeneralTest]:
-        suite = unittest.TestLoader().loadTestsFromTestCase(Test)
-        unittest.TextTestRunner(verbosity=2).run(suite)
+        test_suits.append(unittest.TestLoader().loadTestsFromTestCase(Test))
+    unittest.TextTestRunner(verbosity=2).run(unittest.TestSuite(test_suits))
+