tests: add ws2 api tests for retries

tests/api/test_ws2.py

@@ -0,0 +1,46 @@
+#!/usr/bin/env python3
+
+import unittest
+
+from .fake import WS2Api
+
+from tconnectsync.api.common import ApiException
+
+class TestWS2Api(unittest.TestCase):
+    def fake_get_with_http_500(self, num_times):
+        tries = 0
+        def fake_get(endpoint, query):
+            nonlocal tries, num_times
+            if "therapytimeline2csv" in endpoint:
+                if tries < num_times:
+                    tries += 1
+                    raise ApiException(500, "fake HTTP 500")
+
+                return ""
+            raise NotImplementedError
+
+        return fake_get
+
+    def test_therapy_timeline_csv_works_after_two_retries(self):
+        ws2 = WS2Api()
+
+        ws2.get = self.fake_get_with_http_500(2)
+
+        self.assertEqual(
+            ws2.therapy_timeline_csv('2021-04-01', '2021-04-02'),
+            {
+                "readingData": [],
+                "iobData": [],
+                "basalData": [],
+                "bolusData": []
+            })
+
+    def test_therapy_timeline_csv_fails_after_three_retries(self):
+        ws2 = WS2Api()
+
+        ws2.get = self.fake_get_with_http_500(3)
+
+        self.assertRaises(ApiException, ws2.therapy_timeline_csv, '2021-04-01', '2021-04-02')
+
+if __name__ == '__main__':
+    unittest.main()