Fix bug: Signups for one course don't influence other course anymore

Backend/signups.py

@@ -13,6 +13,7 @@ import json
 from functools import wraps
 from itertools import chain
 
+from bson import ObjectId
 from flask import current_app, abort
 from eve.methods.get import getitem_internal
 from eve.methods.patch import patch_internal
@@ -94,7 +95,10 @@ def update_signups(course):
 
     # Next, count current signups not on waiting list
     collection = current_app.data.driver.db['signups']
-    taken_spots = collection.count({'status': {'$ne': 'waiting'}})
+    taken_spots = collection.count({
+        'course': ObjectId(str(course)),
+        'status': {'$ne': 'waiting'}
+    })
 
     available_spots = total_spots - taken_spots
 
@@ -108,17 +112,12 @@ def update_signups(course):
                               sort=[('_updated', 1), ('nethz', 1)],
                               limit=available_spots)
 
-    signups_to_update = [str(item['_id']) for item in signups
-                         if item['status'] == 'waiting']
+    signup_ids = [item['_id'] for item in signups]
 
-    for signup_id in signups_to_update:
-        patch_internal('signups',
-                       _id=signup_id,
-                       payload={'status': 'reserved'},
-                       concurrency_check=False,
-                       skip_validation=True)
+    collection.update_many({'_id': {'$in': signup_ids}},
+                           {'$set': {'status': 'reserved'}})
 
-    return signups_to_update
+    return [str(item) for item in signup_ids]
 
 
 def mark_as_paid(payments):

Backend/tests/test_signups.py

@@ -15,12 +15,14 @@ from signups import update_signups
 
 def test_success(app):
     """If there are enough spots, the status will be 'reserved'."""
-    with app.admin():  # Admin so we don't need to care about nethz
-        # Create fake courses to sign up to
+    # Create fake courses to sign up to
+    with app.admin():
         course_id = str(app.data.driver.db['courses'].insert({'spots': 10}))
 
+    # Sign up as user
+    with app.user(nethz='nethz'):
         signup = {
-            'nethz': 'Something',
+            'nethz': 'nethz',
             'course': course_id,
         }
 
@@ -96,6 +98,35 @@ def test_not_enough_spots(app):
         assert second_response['status'] == 'waiting'
 
 
+def test_course_independence(app):
+    """Test that signups of one course don't influence another.
+
+    There was a bug in the code that lead to counting any signup for any
+    course. This test should ensure it doesn't happen again.
+    """
+    with app.admin():
+        # Course with a free spot
+        main_course = app.data.driver.db['courses'].insert({'spots': 1})
+
+        # Other course that will get signups
+        other_course = app.data.driver.db['courses'].insert({'spots': 5})
+        for _ in range(5):
+            app.data.driver.db['signups'].insert({'course': other_course})
+
+        # Sign up to course
+        signup = {
+            'nethz': 'Something',
+            'course': str(main_course),
+        }
+
+        response = app.client.post('/signups',
+                                   data=signup,
+                                   assert_status=201)
+
+        # The other signups should have no influence
+        assert response['status'] == 'reserved'
+
+
 def test_update_spots(app):
     """Test the main update function.