Fixed typo and added tests

Change-Id: I463d078b04e55605ed273011cd79bdc1bd88879c

analyticsclient/activity_type.py

@@ -5,4 +5,4 @@ Course activity types.
 ANY = 'any'
 ATTEMPTED_PROBLEM = 'attempted_problem'
 PLAYED_VIDEO = 'played_video'
-POSTED_FORUM = 'posted_form'
+POSTED_FORUM = 'posted_forum'

analyticsclient/tests/test_helpers.py

+from unittest import TestCase
+from analyticsclient import activity_type, demographic
+
+
+class HelperTests(TestCase):
+    """
+    Basic checks for typos.
+    """
+
+    def test_activity_type(self):
+        self.assertEqual('any', activity_type.ANY)
+        self.assertEqual('attempted_problem', activity_type.ATTEMPTED_PROBLEM)
+        self.assertEqual('played_video', activity_type.PLAYED_VIDEO)
+        self.assertEqual('posted_forum', activity_type.POSTED_FORUM)
+
+    def test_demographic(self):
+        self.assertEqual('birth_year', demographic.BIRTH_YEAR)
+        self.assertEqual('education', demographic.EDUCATION)
+        self.assertEqual('gender', demographic.GENDER)