diff --git a/tests/gtfs/test_cleaners.py b/tests/gtfs/test_cleaners.py
index 9e52185d..880f95f6 100644
--- a/tests/gtfs/test_cleaners.py
+++ b/tests/gtfs/test_cleaners.py
@@ -10,6 +10,7 @@
     drop_trips,
     clean_consecutive_stop_fast_travel_warnings,
     clean_multiple_stop_fast_travel_warnings,
+    core_cleaners,
 )
 
 
@@ -275,3 +276,88 @@ def test_clean_multiple_stop_fast_travel_warnings_on_pass(
         clean_multiple_stop_fast_travel_warnings(
             gtfs=gtfs_fixture, validate=True
         )
+
+
+class TestCoreCleaner(object):
+    """Tests for core_cleaners().
+
+    Notes
+    -----
+    There are no passing tests for this function as it relies on function from
+    gtfs-kit which have already been tested.
+
+    """
+
+    @pytest.mark.parametrize(
+        (
+            "clean_ids, clean_times, clean_route_short_names, drop_zombies, "
+            "raises, match"
+        ),
+        [
+            (
+                1,
+                True,
+                True,
+                True,
+                TypeError,
+                r".*expected .*bool.* Got .*int.*",
+            ),
+            (
+                True,
+                dict(),
+                True,
+                True,
+                TypeError,
+                r".*expected .*bool.* Got .*dict.*",
+            ),
+            (
+                True,
+                True,
+                "test string",
+                True,
+                TypeError,
+                r".*expected .*bool.* Got .*str.*",
+            ),
+            (
+                True,
+                True,
+                True,
+                2.12,
+                TypeError,
+                r".*expected .*bool.* Got .*float.*",
+            ),
+        ],
+    )
+    def test_core_claners_defence(
+        self,
+        gtfs_fixture,
+        clean_ids,
+        clean_times,
+        clean_route_short_names,
+        drop_zombies,
+        raises,
+        match,
+    ):
+        """Defensive tests for core_cleaners."""
+        with pytest.raises(raises, match=match):
+            gtfs_fixture.is_valid()
+            core_cleaners(
+                gtfs_fixture,
+                clean_ids,
+                clean_times,
+                clean_route_short_names,
+                drop_zombies,
+            )
+
+    def test_core_cleaners_drop_zombies_warns(self, gtfs_fixture):
+        """Test that warnings are emitted when shape_id isn't present in...
+
+        trips.
+        """
+        gtfs_fixture.feed.trips.drop("shape_id", axis=1, inplace=True)
+        with pytest.warns(
+            UserWarning,
+            match=r".*drop_zombies cleaner was unable to operate.*",
+        ):
+            gtfs_fixture.is_valid(validators={"core_validation": None})
+            gtfs_fixture.clean_feed()