diff --git a/.github/workflows/test-only.yml b/.github/workflows/test-only.yml
index 3064e97d..f7aec92e 100644
--- a/.github/workflows/test-only.yml
+++ b/.github/workflows/test-only.yml
@@ -51,6 +51,7 @@ jobs:
         run: |
           # Unit tests
           docker run test-changedetectionio  bash -c 'python3 -m unittest changedetectionio.tests.unit.test_notification_diff'
+          docker run test-changedetectionio  bash -c 'python3 -m unittest changedetectionio.tests.unit.test_watch_model_diff'
           
           # All tests
           docker run --network changedet-network  test-changedetectionio  bash -c 'cd changedetectionio && ./run_basic_tests.sh'
diff --git a/changedetectionio/model/Watch.py b/changedetectionio/model/Watch.py
index 8d58ca46..802a7919 100644
--- a/changedetectionio/model/Watch.py
+++ b/changedetectionio/model/Watch.py
@@ -271,15 +271,18 @@ class model(dict):
 
         """Unfortunately for now timestamp is stored as string key"""
         keys = list(self.history.keys())
+
         last_viewed = self.get('last_viewed')
-        prev_k=keys[0]
-        for k in sorted(keys, key=lambda x: int(x)):
-            if int(k) >= int(last_viewed):
+        prev_k = keys[0]
+        sorted_keys = sorted(keys, key=lambda x: int(x))
+        sorted_keys.reverse()
+
+        for k in sorted_keys:
+            if int(k) < int(last_viewed):
                 return prev_k
             prev_k = k
 
-        #@check this, return last if not found?
-        return keys[-1]
+        return keys[0]
 
     def get_history_snapshot(self, timestamp):
         import brotli
diff --git a/changedetectionio/tests/unit/test_watch_model.py b/changedetectionio/tests/unit/test_watch_model.py
new file mode 100644
index 00000000..d7d26d71
--- /dev/null
+++ b/changedetectionio/tests/unit/test_watch_model.py
@@ -0,0 +1,31 @@
+#!/usr/bin/python3
+
+# run from dir above changedetectionio/ dir
+# python3 -m unittest changedetectionio.tests.unit.test_notification_diff
+
+import unittest
+import os
+
+from changedetectionio.model import Watch
+
+# mostly
+class TestDiffBuilder(unittest.TestCase):
+
+    def test_watch_module(self):
+        import uuid as uuid_builder
+        watch = Watch.model(datastore_path='/tmp', default={})
+        watch.ensure_data_dir_exists()
+
+        watch['last_viewed'] = 110
+
+        watch.save_history_text(contents=b"hello world", timestamp=100, snapshot_id=str(uuid_builder.uuid4()))
+        watch.save_history_text(contents=b"hello world", timestamp=105, snapshot_id=str(uuid_builder.uuid4()))
+        watch.save_history_text(contents=b"hello world", timestamp=109, snapshot_id=str(uuid_builder.uuid4()))
+        watch.save_history_text(contents=b"hello world", timestamp=112, snapshot_id=str(uuid_builder.uuid4()))
+        watch.save_history_text(contents=b"hello world", timestamp=115, snapshot_id=str(uuid_builder.uuid4()))
+
+        p = watch.get_next_snapshot_key_to_last_viewed
+        assert p == "112", "Correct last-viewed timestamp was detected"
+
+if __name__ == '__main__':
+    unittest.main()