- Fix pagination bug (#305)

- Add unit test for pagination

Author: nwithan8

Diff for: easypost/services/base_service.py

@@ -104,7 +104,7 @@ def _get_next_page_resources(
         response = Requestor(self._client).request(method=RequestMethod.GET, url=url, params=params)
 
         response_array: List[Any] = response.get(url[1:])  # type: ignore
-        if response is None or len(response_array) == 0 or not response.get("has_more"):
+        if response is None or len(response_array) == 0:
             raise EndOfPaginationError(NO_MORE_PAGES_ERROR)
 
         return convert_to_easypost_object(response=response)

Diff for: tests/test_base_service.py

@@ -0,0 +1,69 @@
+from unittest.mock import patch
+
+import pytest
+from easypost.constant import NO_MORE_PAGES_ERROR
+from easypost.errors import EndOfPaginationError
+
+
+@pytest.mark.vcr()  # Cassette not needed due to mocking, but used to avoid making real bogus API calls
+def test_get_next_page_collects_all_pages(test_client):
+    page_size = 1  # Doesn't matter what this is, we're mocking the response
+    all_results = []
+
+    # Using scanforms as an example, but this should work for any service since it's a base class method
+    first_page_response = {
+        "scan_forms": [
+            {
+                "id": "sf_123",
+            }
+        ],
+        "has_more": True,
+    }
+
+    # Mock the initial "get all scanforms" call
+    with patch("easypost.requestor.Requestor.request", return_value=first_page_response):
+        first_page = test_client.scan_form.all(page_size=page_size)
+        all_results += first_page["scan_forms"]
+        previous_page = first_page
+
+    second_page_response = {
+        "scan_forms": [
+            {
+                "id": "sf_456",
+            }
+        ],
+        "has_more": True,
+    }
+
+    # Mock the first "get next page" call with more to collect after
+    # (current page "has_more" = True, next page "has_more" = True)
+    with patch("easypost.requestor.Requestor.request", return_value=second_page_response):
+        next_page = test_client.scan_form.get_next_page(scan_forms=previous_page, page_size=page_size)  # type: ignore
+        all_results += next_page["scan_forms"]
+        previous_page = next_page
+
+    third_page_response = {
+        "scan_forms": [
+            {
+                "id": "sf_789",
+            }
+        ],
+        "has_more": False,
+    }
+
+    # Mock the second "get next page" call with no more to collect
+    # (current page "has_more" = True, next page "has_more" = False)
+    with patch("easypost.requestor.Requestor.request", return_value=third_page_response):
+        next_page = test_client.scan_form.get_next_page(scan_forms=previous_page, page_size=page_size)  # type: ignore
+        all_results += next_page["scan_forms"]
+        previous_page = next_page
+
+    # Verify we have all scan_forms (from the initial "get all scanforms" and two subsequent "get next page" calls)
+    # Ensures that no guard clauses inside the "get next page" method are preventing us from collecting all scanforms
+    assert len(all_results) == 3
+
+    # Now that the previous page has "has_more" = False, it should throw an error before even making the API call
+    with pytest.raises(EndOfPaginationError) as error:
+        _ = test_client.scan_form.get_next_page(scan_forms=previous_page, page_size=page_size)  # type: ignore
+
+    assert error.value.message == NO_MORE_PAGES_ERROR