Move `run_concurrently` from `tests/utils` to `src/oscar/test/utils`

This change will allow to import `run_concurrently` helper for test
purposes in other libraries.

src/oscar/test/utils.py

@@ -1,4 +1,8 @@
+import queue
+import threading
+
 from django.contrib.auth.models import AnonymousUser
+from django.db import connection
 from django.contrib.messages.storage.fallback import FallbackStorage
 from django.contrib.sessions.backends.db import SessionStore
 from django.core.signing import Signer
@@ -26,3 +30,35 @@ class RequestFactory(BaseRequestFactory):
         request.cookies_to_delete = []
 
         return request
+
+
+def run_concurrently(fn, kwargs=None, num_threads=5):
+    exceptions = queue.Queue()
+
+    def worker(**kwargs):
+        try:
+            fn(**kwargs)
+        except Exception as exc:
+            exceptions.put(exc)
+        else:
+            exceptions.put(None)
+        finally:
+            connection.close()
+
+    kwargs = kwargs if kwargs is not None else {}
+
+    # Run them
+    threads = [
+        threading.Thread(target=worker, name='thread-%d' % i, kwargs=kwargs)
+        for i in range(num_threads)
+    ]
+    try:
+        for thread in threads:
+            thread.start()
+    finally:
+        for thread in threads:
+            thread.join()
+
+    # Retrieve exceptions
+    exceptions = [exceptions.get(block=False) for i in range(num_threads)]
+    return [exc for exc in exceptions if exc is not None]

tests/integration/order/test_creator.py

@@ -19,7 +19,7 @@ from oscar.apps.voucher.models import Voucher
 from oscar.core.loading import get_class
 from oscar.test import factories
 from oscar.test.basket import add_product
-from tests.utils import run_concurrently
+from oscar.test.utils import run_concurrently
 
 Range = get_class('offer.models', 'Range')
 Benefit = get_class('offer.models', 'Benefit')

tests/utils.py

@@ -1,36 +0,0 @@
-import queue
-import threading
-
-from django.db import connection
-
-
-def run_concurrently(fn, kwargs=None, num_threads=5):
-    exceptions = queue.Queue()
-
-    def worker(**kwargs):
-        try:
-            fn(**kwargs)
-        except Exception as exc:
-            exceptions.put(exc)
-        else:
-            exceptions.put(None)
-        finally:
-            connection.close()
-
-    kwargs = kwargs if kwargs is not None else {}
-
-    # Run them
-    threads = [
-        threading.Thread(target=worker, name='thread-%d' % i, kwargs=kwargs)
-        for i in range(num_threads)
-    ]
-    try:
-        for thread in threads:
-            thread.start()
-    finally:
-        for thread in threads:
-            thread.join()
-
-    # Retrieve exceptions
-    exceptions = [exceptions.get(block=False) for i in range(num_threads)]
-    return [exc for exc in exceptions if exc is not None]