test(urls): cover TransitAgencyPathConverter use-cases

- active agency
- active agency with hyphens in slug
- inactive agency
- unknown agency

Author: thekaveman

tests/pytest/core/test_urls.py

@@ -0,0 +1,47 @@
+"""
+h/t to this blog post for the inspiration for these tests
+https://adamj.eu/tech/2025/08/01/django-custom-url-converter-string/
+"""
+
+import pytest
+from django.urls import path, reverse
+
+# Import forces registration
+from benefits.core.urls import TransitAgencyPathConverter  # noqa: F401
+
+urlpatterns = [
+    path(
+        "<agency:agency>",
+        lambda *args, **kwargs: None,  # dummy view
+        name="sample",
+    )
+]
+sample_path = urlpatterns[0]
+
+
+@pytest.mark.django_db
+class TestTransitAgencyPathConverter:
+    def test_active_agency(self, model_TransitAgency):
+        result = sample_path.resolve(model_TransitAgency.slug)
+        assert result.kwargs["agency"] == model_TransitAgency
+
+        result = reverse("sample", urlconf=__name__, kwargs={"agency": model_TransitAgency})
+        assert result == f"/{model_TransitAgency.slug}"
+
+    def test_active_agency__hyphen_slug(self, model_TransitAgency):
+        model_TransitAgency.slug = "c-s-t"
+        model_TransitAgency.save()
+
+        result = sample_path.resolve(model_TransitAgency.slug)
+        assert result.kwargs["agency"] == model_TransitAgency
+
+        result = reverse("sample", urlconf=__name__, kwargs={"agency": model_TransitAgency})
+        assert result == f"/{model_TransitAgency.slug}"
+
+    def test_inactive_agency(self, model_TransitAgency_inactive):
+        result = sample_path.resolve(model_TransitAgency_inactive.slug)
+        assert result is None
+
+    def test_unknown_agency(self):
+        result = sample_path.resolve("unknown")
+        assert result is None