Use standard management file instead of runtests

manage.py

@@ -0,0 +1,22 @@
+#!/usr/bin/env python
+import os
+import sys
+
+if __name__ == "__main__":
+    os.environ.setdefault("DJANGO_SETTINGS_MODULE", "tests.settings")
+    try:
+        from django.core.management import execute_from_command_line
+    except ImportError:
+        # The above import may fail for some other reason. Ensure that the
+        # issue is really that Django is missing to avoid masking other
+        # exceptions on Python 2.
+        try:
+            import django
+        except ImportError:
+            raise ImportError(
+                "Couldn't import Django. Are you sure it's installed and "
+                "available on your PYTHONPATH environment variable? Did you "
+                "forget to activate a virtual environment?"
+            )
+        raise
+    execute_from_command_line(sys.argv)

runtests.py

@@ -1,24 +0,0 @@
-# This file mainly exists to allow python setup.py test to work.
-# flake8: noqa
-import os
-import sys
-
-os.environ['DJANGO_SETTINGS_MODULE'] = 'tests.settings'
-test_dir = os.path.join(os.path.dirname(__file__), 'rest_auth')
-sys.path.insert(0, test_dir)
-
-import django
-from django.test.utils import get_runner
-from django.conf import settings
-
-
-def runtests():
-    TestRunner = get_runner(settings)
-    test_runner = TestRunner(verbosity=1, interactive=True)
-    if hasattr(django, 'setup'):
-        django.setup()
-    failures = test_runner.run_tests(['rest_auth'])
-    sys.exit(bool(failures))
-
-if __name__ == '__main__':
-    runtests()