diff --git a/metadata_fetcher/fetchers/Fetcher.py b/metadata_fetcher/fetchers/Fetcher.py
index 8b83fac69..11dd7a0f8 100644
--- a/metadata_fetcher/fetchers/Fetcher.py
+++ b/metadata_fetcher/fetchers/Fetcher.py
@@ -52,6 +52,9 @@ def fetch_page(self):
             f"[{self.collection_id}]: fetching page {self.write_page} "
             f"at {page.get('url')}"
         )
+        if 'url' not in page:
+            raise InvalidHarvestEndpoint(
+                f"[{self.collection_id}]: invalid harvest endpoint")
         try:
             response = requests.get(**page)
             response.raise_for_status()
@@ -91,7 +94,7 @@ def build_fetch_request(self):
         {'headers': {}, 'params': {}} or any other options accepted by
         https://docs.python-requests.org/en/latest/api/#requests.get
         """
-        pass
+        raise NotImplementedError
 
     def get_records(self, http_resp):
         """parses http_resp from institutional API into a list of records
@@ -100,7 +103,7 @@ def get_records(self, http_resp):
         by json.dumps into json line format; takes as an argument:
         https://docs.python-requests.org/en/latest/api/#requests.Response
         """
-        pass
+        raise NotImplementedError
 
     def increment(self, http_resp):
         """increment internal state for fetching the next page
diff --git a/metadata_fetcher/fetchers/oai_fetcher.py b/metadata_fetcher/fetchers/oai_fetcher.py
index 21efec36c..45b1c4d41 100644
--- a/metadata_fetcher/fetchers/oai_fetcher.py
+++ b/metadata_fetcher/fetchers/oai_fetcher.py
@@ -17,7 +17,7 @@ class OaiFetcher(Fetcher):
     def __init__(self, params):
         super(OaiFetcher, self).__init__(params)
 
-        self.oai = params.get('harvest_data')
+        self.oai = params.get('harvest_data', {})
 
         if self.oai.get('harvest_extra_data'):
             # see if we have a query string,
@@ -68,8 +68,13 @@ def build_fetch_request(self):
 
     def check_page(self, http_resp: requests.Response) -> int:
         xml_resp = ElementTree.fromstring(http_resp.content)
-        xml_hits = xml_resp.find(
-            'oai2:ListRecords', NAMESPACE).findall('oai2:record', NAMESPACE)
+
+        xml_list = xml_resp.find('oai2:ListRecords', NAMESPACE)
+        if xml_list is None:
+            raise ValueError(
+                "No records found in response from {http_resp.request.url}")
+
+        xml_hits = xml_list.findall('oai2:record', NAMESPACE)
 
         if len(xml_hits) > 0:
             logging.debug(