More adaptions to testing

.coveragerc

@@ -4,6 +4,7 @@ plugins =
 omit =
     node_modules/*
     .virtualenv/*
+    import_libravatar.py
 
 [html]
 extra_css = coverage_extra_style.css

config.py

@@ -95,7 +95,7 @@ BOOTSTRAP4 = {
 }
 
 if 'EMAIL_BACKEND' in os.environ:
-    EMAIL_BACKEND = os.environ['EMAIL_BACKEND']
+    EMAIL_BACKEND = os.environ['EMAIL_BACKEND']  # pragma: no cover
 else:
     if 'test' in sys.argv or 'collectstatic' in sys.argv:
         EMAIL_BACKEND = 'django.core.mail.backends.locmem.EmailBackend'