refactor and add tests

tests/unit/test_hooks.py

@@ -0,0 +1,13 @@
+import pytest
+
+from wagtail_personalisation import wagtail_hooks as hooks
+from wagtail_personalisation.models import Segment
+
+
+@pytest.mark.django_db
+def test_check_for_variations(segmented_page):
+    segments = Segment.objects.all()
+    page = segmented_page.canonical_page
+
+    variations = hooks._check_for_variations(segments, page)
+    assert variations