Added comments to document race condition

mycroft/skills/mycroft_skill/mycroft_skill.py

@@ -411,7 +411,16 @@ class MycroftSkill:
         return False
 
     def __get_response(self):
-        """Helper to get a reponse from the user
+        """Helper to get a response from the user
+
+        NOTE:  There is a race condition here.  There is a small amount of
+        time between the end of the device speaking and the converse method
+        being overridden in this method.  If an utterance is injected during
+        this time, the wrong converse method is executed.  The condition is
+        hidden during normal use due to the amount of time it takes a user
+        to speak a response. The condition is revealed when an automated
+        process injects an utterance quicker than this method can flip the
+        converse methods.
 
         Returns:
             str: user's response or None on a timeout

test/integrationtests/voight_kampff/features/steps/utterance_responses.py

@@ -235,6 +235,12 @@ def then_contains(context, text):
 @then('the user replies "{text}"')
 @then('the user says "{text}"')
 def then_user_follow_up(context, text):
+    """Send a user response after being prompted by device.
+
+    The sleep after the device is finished speaking is to address a race
+    condition in the MycroftSkill base class conversational code.  It can
+    be removed when the race condition is addressed.
+    """
     wait_while_speaking()
     time.sleep(2)
     context.bus.emit(Message('recognizer_loop:utterance',