Improving testing for when absent 'date' parameter

The tests were too complicated and their names were unclear. We now only have one test which just checks what it needs to in order to test the functionality.

tests/read/test_parse_request_args.py

@@ -145,7 +145,7 @@ def test_one_collect_is_parsed_with_custom_method(self):
         assert_that(args['collect'], is_([("some_key", "mean")]))
 
     @freeze_time('2014-01-09 00:00:00')
-    def test_now_and_positive_delta_sets_start_end_window(self):
+    def test_no_date_means_now(self):
         request_args = MultiDict([
             ('period', 'day'),
             ('delta', '3'),
@@ -156,24 +156,6 @@ def test_now_and_positive_delta_sets_start_end_window(self):
         assert_that(args['start_at'], is_(
             datetime(2014, 1, 9, 0, 0, 0, tzinfo=pytz.UTC)))
 
-        assert_that(args['end_at'], is_(
-            datetime(2014, 1, 12, 0, 0, 0, tzinfo=pytz.UTC)))
-
-    @freeze_time('2014-01-09 00:00:00')
-    def test_now_and_negative_delta_sets_start_end_window(self):
-        request_args = MultiDict([
-            ('period', 'day'),
-            ('delta', '-3'),
-        ])
-
-        args = parse_request_args(request_args)
-
-        assert_that(args['start_at'], is_(
-            datetime(2014, 1, 6, 0, 0, 0, tzinfo=pytz.UTC)))
-
-        assert_that(args['end_at'], is_(
-            datetime(2014, 1, 9, 0, 0, 0, tzinfo=pytz.UTC)))
-
     def test_date_on_boundary_and_positive_delta(self):
         request_args = MultiDict([
             ('date', '2014-01-09T00:00:00+00:00'),