feat: raise exception if zero datasets fetched from registry

Author: tillywoodfield

oc4ids_datastore_pipeline/registry.py

@@ -22,9 +22,13 @@ def fetch_registered_datasets() -> dict[str, str]:
         }
         registered_datasets_count = len(registered_datasets)
         logger.info(f"Fetched URLs for {registered_datasets_count} datasets")
-        return registered_datasets
     except Exception as e:
         raise Exception("Failed to fetch datasets list from registry", e)
+    if registered_datasets_count < 1:
+        raise Exception(
+            "Zero datasets returned from registry, likely an upstream error"
+        )
+    return registered_datasets
 
 
 def fetch_license_mappings() -> dict[str, str]:

tests/test_registry.py

@@ -38,6 +38,20 @@ def test_fetch_registered_datasets_raises_failure_exception(
     assert "Mocked exception" in str(exc_info.value)
 
 
+def test_fetch_registered_datasets_raises_exception_when_no_datasets(
+    mocker: MockerFixture,
+) -> None:
+    mock_response = MagicMock()
+    mock_response.json.return_value = {"records": {}}
+    patch_get = mocker.patch("oc4ids_datastore_pipeline.pipeline.requests.get")
+    patch_get.return_value = mock_response
+
+    with pytest.raises(Exception) as exc_info:
+        fetch_registered_datasets()
+
+    assert "Zero datasets returned from registry" in str(exc_info.value)
+
+
 def test_fetch_license_mappings(mocker: MockerFixture) -> None:
     mock_response = MagicMock()
     mock_response.json.return_value = {