Add feature test to check idempotency in created course events

Author: aliondev

tests/apps/mooc_backend/features/courses_counter/get-courses-counter.feature

@@ -30,3 +30,67 @@ Feature: Obtain the total number of courses
       "total": 1
     }
     """
+
+  Scenario: With more than one course having duplicates
+    Given I send an event to the event bus:
+    """
+    {
+      "data": {
+        "id": "c77fa036-cbc7-4414-996b-c6a7a93cae09",
+        "type": "course.created",
+        "occurred_on": "2019-08-08T08:37:32+00:00",
+        "attributes": {
+          "id": "8c900b20-e04a-4777-9183-32faab6d2fb5",
+          "name": "DDD en PHP!",
+          "duration": "25 hours"
+        },
+        "meta" : {
+          "host": "111.26.06.93"
+        }
+      }
+    }
+    """
+    And I send an event to the event bus:
+    """
+    {
+      "data": {
+        "id": "8c4a4ed8-9458-489e-a167-b099d81fa096",
+        "type": "course.created",
+        "occurred_on": "2019-08-09T08:36:32+00:00",
+        "attributes": {
+          "id": "8c4a4ed8-9458-489e-a167-b099d81fa096",
+          "name": "DDD en Java!",
+          "duration": "24 hours"
+        },
+        "meta" : {
+          "host": "111.26.06.93"
+        }
+      }
+    }
+    """
+    And I send an event to the event bus:
+    """
+    {
+      "data": {
+        "id": "8c4a4ed8-9458-489e-a167-b099d81fa096",
+        "type": "course.created",
+        "occurred_on": "2019-08-09T08:36:32+00:00",
+        "attributes": {
+          "id": "8c4a4ed8-9458-489e-a167-b099d81fa096",
+          "name": "DDD en Java!",
+          "duration": "24 hours"
+        },
+        "meta" : {
+          "host": "111.26.06.93"
+        }
+      }
+    }
+    """
+    When I send a GET request to "/courses-counter"
+    Then the response status code should be 200
+    And the response content should be:
+    """
+    {
+      "total": 2
+    }
+    """