make test course loading deterministic by using course_id

common/test/data/full/course.xml

-<course filename="6.002_Spring_2012" slug="6.002_Spring_2012" graceperiod="1 day 12 hours 59 minutes 59 seconds" showanswer="attempted" rerandomize="never" name="6.002 Spring 2012" start="2015-07-17T12:00" course="full" org="edx"/>
+<course filename="6.002_Spring_2012" slug="6.002_Spring_2012" graceperiod="1 day 12 hours 59 minutes 59 seconds" showanswer="attempted" rerandomize="never" name="6.002 Spring 2012" start="2015-07-17T12:00" course="full" org="edX"/>

lms/djangoapps/courseware/tests/tests.py

@@ -294,12 +294,12 @@ class TestNavigation(PageLoader):
         xmodule.modulestore.django._MODULESTORES = {}
         courses = modulestore().get_courses()
 
-        def find_course(name):
+        def find_course(course_id):
             """Assumes the course is present"""
-            return [c for c in courses if c.location.course==name][0]
+            return [c for c in courses if c.id==course_id][0]
 
-        self.full = find_course("full")
-        self.toy = find_course("toy")
+        self.full = find_course("edX/full/6.002_Spring_2012")
+        self.toy = find_course("edX/toy/2012_Fall")
 
         # Create two accounts
         self.student = 'view@test.com'
@@ -352,12 +352,12 @@ class TestViewAuth(PageLoader):
         xmodule.modulestore.django._MODULESTORES = {}
         courses = modulestore().get_courses()
 
-        def find_course(name):
+        def find_course(course_id):
             """Assumes the course is present"""
-            return [c for c in courses if c.location.course==name][0]
+            return [c for c in courses if c.id==course_id][0]
 
-        self.full = find_course("full")
-        self.toy = find_course("toy")
+        self.full = find_course("edX/full/6.002_Spring_2012")
+        self.toy = find_course("edX/toy/2012_Fall")
 
         # Create two accounts
         self.student = 'view@test.com'