Use correct filenames for the tests (and split some)

tests/unit/test_rules_referral.py

@@ -0,0 +1,15 @@
+
+import pytest
+
+from tests.factories.rule import ReferralRuleFactory
+from tests.factories.segment import SegmentFactory
+
+
+@pytest.mark.django_db
+def test_referral_rule_create():
+    segment = SegmentFactory(name='Referral')
+    referral_rule = ReferralRuleFactory(
+        regex_string='test.test',
+        segment=segment)
+
+    assert referral_rule.regex_string == 'test.test'