First tests for _is_drawable_clicked.

Also, uncover some more inconsistencies for #30.

components/core.py

@@ -213,6 +213,9 @@ def screen_size(self):
 
     # TODO Is this appropriate for a decorator?
     def _is_drawable_clicked(self, drawable, pos):
+        """
+        Position is taken as a (width, height) offset.
+        """
         width_limit = drawable.draw_offset[1] + drawable.max_size[0]
         height_limit = drawable.draw_offset[0] + drawable.max_size[1]
         in_width = drawable.draw_offset[1] <= pos[0] <= width_limit

tests/components/core_tests.py

@@ -1,4 +1,5 @@
 from components.core import DebugQueue, GameConfig, GameModel, GameScreen, GameLoop, GameLoopEvents
+from components.drawable import Drawable
 from components.subscriber_pattern import Subscriber
 from mock import patch
 from StringIO import StringIO
@@ -137,6 +138,12 @@ def test_debug_provisions(self):
             screen_debug.screen_size
         )
 
+    def test_is_drawable_clicked_happy(self):
+        sample_drawable = Drawable((0, 0), 100, 88)
+        cfg = GameConfig(window_size=(200, 160))
+        screen = GameScreen(cfg, GameModel())
+        self.assertTrue(screen._is_drawable_clicked(sample_drawable, (90, 44)))
+
 class DebugQueueTest(unittest.TestCase):
 
     def test_log_q_growth(self):