Event-testing pattern should be supported by a mixin.

common/test/acceptance/tests/discussion/test_cohort_management.py

@@ -5,13 +5,11 @@ End-to-end tests related to the cohort management on the LMS Instructor Dashboar
 
 from datetime import datetime
 
-from pymongo import MongoClient
-
 from pytz import UTC, utc
 from bok_choy.promise import EmptyPromise
 from nose.plugins.attrib import attr
 from .helpers import CohortTestMixin
-from ..helpers import UniqueCourseTest, create_user_partition_json
+from ..helpers import UniqueCourseTest, EventsTestMixin, create_user_partition_json
 from xmodule.partitions.partitions import Group
 from ...fixtures.course import CourseFixture
 from ...pages.lms.auto_auth import AutoAuthPage
@@ -23,7 +21,7 @@ import uuid
 
 
 @attr('shard_3')
-class CohortConfigurationTest(UniqueCourseTest, CohortTestMixin):
+class CohortConfigurationTest(EventsTestMixin, UniqueCourseTest, CohortTestMixin):
     """
     Tests for cohort management on the LMS Instructor Dashboard
     """
@@ -34,8 +32,6 @@ class CohortConfigurationTest(UniqueCourseTest, CohortTestMixin):
         """
         super(CohortConfigurationTest, self).setUp()
 
-        self.event_collection = MongoClient()["test"]["events"]
-
         # create course with cohorts
         self.manual_cohort_name = "ManualCohort1"
         self.auto_cohort_name = "AutoCohort1"

common/test/acceptance/tests/helpers.py

@@ -6,10 +6,12 @@ import unittest
 import functools
 import requests
 import os
+from datetime import datetime
 from path import path
 from bok_choy.javascript import js_defined
 from bok_choy.web_app_test import WebAppTest
 from opaque_keys.edx.locator import CourseLocator
+from pymongo import MongoClient
 from xmodule.partitions.partitions import UserPartition
 from xmodule.partitions.tests.test_partitions import MockUserPartitionScheme
 from selenium.webdriver.support.select import Select
@@ -236,24 +238,6 @@ def element_has_text(page, css_selector, text):
     return text_present
 
 
-def assert_event_emitted_num_times(event_collection, event_name, event_time, event_user_id, num_times_emitted):
-    """
-    Tests the number of times a particular event was emitted.
-    :param event_collection: MongoClient instance to query.
-    :param event_name: Expected event name (e.g., "edx.course.enrollment.activated")
-    :param event_time: Latest expected time, after which the event would fire (e.g., the beginning of the test case)
-    """
-    assert(
-        event_collection.find(
-            {
-                "name": event_name,
-                "time": {"$gt": event_time},
-                "event.user_id": int(event_user_id),
-            }
-        ).count() == num_times_emitted
-    )
-
-
 def get_modal_alert(browser):
     """
     Returns instance of modal alert box shown in browser after waiting
@@ -263,6 +247,35 @@ def get_modal_alert(browser):
     return browser.switch_to.alert
 
 
+class EventsTestMixin(object):
+    """
+    Helpers and setup for running tests that evaluate events emitted
+    """
+    def setUp(self):
+        super(EventsTestMixin, self).setUp()
+        self.event_collection = MongoClient()["test"]["events"]
+        self.event_collection.drop()
+        self.start_time = datetime.now()
+
+    def assert_event_emitted_num_times(self, event_name, event_time, event_user_id, num_times_emitted):
+        """
+        Tests the number of times a particular event was emitted.
+        :param event_name: Expected event name (e.g., "edx.course.enrollment.activated")
+        :param event_time: Latest expected time, after which the event would fire (e.g., the beginning of the test case)
+        :param event_user_id: user_id expected in the event
+        :param num_times_emitted: number of times the event is expected to appear since the event_time
+        """
+        self.assertEqual(
+            self.event_collection.find(
+                {
+                    "name": event_name,
+                    "time": {"$gt": event_time},
+                    "event.user_id": int(event_user_id),
+                }
+            ).count(), num_times_emitted
+        )
+
+
 class UniqueCourseTest(WebAppTest):
     """
     Test that provides a unique course ID.

common/test/acceptance/tests/lms/test_lms.py

@@ -3,21 +3,19 @@
 End-to-end tests for the LMS.
 """
 
-from datetime import datetime
 from textwrap import dedent
 from unittest import skip
 from nose.plugins.attrib import attr
-from pymongo import MongoClient
 
 from bok_choy.promise import EmptyPromise
 from bok_choy.web_app_test import WebAppTest
 from ..helpers import (
     UniqueCourseTest,
+    EventsTestMixin,
     load_data_str,
     generate_course_key,
     select_option_by_value,
-    element_has_text,
-    assert_event_emitted_num_times
+    element_has_text
 )
 from ...pages.lms.auto_auth import AutoAuthPage
 from ...pages.lms.create_mode import ModeCreationPage
@@ -201,7 +199,7 @@ class RegisterFromCombinedPageTest(UniqueCourseTest):
 
 
 @attr('shard_1')
-class PayAndVerifyTest(UniqueCourseTest):
+class PayAndVerifyTest(EventsTestMixin, UniqueCourseTest):
     """Test that we can proceed through the payment and verification flow."""
     def setUp(self):
         """Initialize the test.
@@ -217,8 +215,6 @@ class PayAndVerifyTest(UniqueCourseTest):
         self.upgrade_page = PaymentAndVerificationFlow(self.browser, self.course_id, entry_point='upgrade')
         self.fake_payment_page = FakePaymentPage(self.browser, self.course_id)
         self.dashboard_page = DashboardPage(self.browser)
-        self.event_collection = MongoClient()["test"]["events"]
-        self.start_time = datetime.now()
 
         # Create a course
         CourseFixture(
@@ -252,8 +248,7 @@ class PayAndVerifyTest(UniqueCourseTest):
         self.fake_payment_page.submit_payment()
 
         # Expect enrollment activated event
-        assert_event_emitted_num_times(
-            self.event_collection,
+        self.assert_event_emitted_num_times(
             "edx.course.enrollment.activated",
             self.start_time,
             student_id,
@@ -261,8 +256,7 @@ class PayAndVerifyTest(UniqueCourseTest):
         )
 
         # Expect that one mode_changed enrollment event fired as part of the upgrade
-        assert_event_emitted_num_times(
-            self.event_collection,
+        self.assert_event_emitted_num_times(
             "edx.course.enrollment.mode_changed",
             self.start_time,
             student_id,
@@ -307,8 +301,7 @@ class PayAndVerifyTest(UniqueCourseTest):
         self.fake_payment_page.submit_payment()
 
         # Expect enrollment activated event
-        assert_event_emitted_num_times(
-            self.event_collection,
+        self.assert_event_emitted_num_times(
             "edx.course.enrollment.activated",
             self.start_time,
             student_id,
@@ -346,8 +339,7 @@ class PayAndVerifyTest(UniqueCourseTest):
         self.fake_payment_page.submit_payment()
 
         # Expect that one mode_changed enrollment event fired as part of the upgrade
-        assert_event_emitted_num_times(
-            self.event_collection,
+        self.assert_event_emitted_num_times(
             "edx.course.enrollment.mode_changed",
             self.start_time,
             student_id,
@@ -355,8 +347,7 @@ class PayAndVerifyTest(UniqueCourseTest):
         )
 
         # Expect no enrollment activated event
-        assert_event_emitted_num_times(
-            self.event_collection,
+        self.assert_event_emitted_num_times(
             "edx.course.enrollment.activated",
             self.start_time,
             student_id,