Bugfix: return empty but don't 500 if we hit the TB test summary API …

…for a patient with no TB Episode

plugins/tb/api.py

@@ -55,6 +55,15 @@ class TbTests(LoginRequiredViewset):
 
     @patient_from_pk
     def retrieve(self, request, patient):
+        tb_patient = patient.episode_set.filter(category_name=TBEpisode.display_name).exists()
+        # There is nowhere in the UI where these results are displayed if no TB episode
+        # exists, but due to questionable implementation details of episode detail views,
+        # sometimes this can be called for non-tb patients.
+        # If they have old -ve TB screening tests this raises an exception - prevent that
+        # by simply returning fast.
+        if not tb_patient:
+            return json_response({})
+
         # observations of a singl test are split across models, fetch them
         # and group them back by lab number
         smears = list(models.AFBSmear.objects.filter(

plugins/tb/tests/test_api.py

@@ -84,3 +84,25 @@ def test_get_lab_tests(self):
             ]
         }
         self.assertEqual(result.json(), expected)
+
+
+class TestTBTests(OpalTestCase):
+
+    def setUp(self):
+        self.request = self.rf.get("/")
+        self.patient, _ = self.new_patient_and_episode_please()
+        self.url = reverse(
+            'tb_tests-detail',
+            kwargs={"pk": self.patient.id},
+            request=self.request
+        )
+        self.assertTrue(
+            self.client.login(
+                username=self.user.username, password=self.PASSWORD
+            )
+        )
+
+    def test_no_TB_epispde(self):
+        result = self.client.get(self.url)
+        expected = {}
+        self.assertEqual(result.json(), expected)