diff --git a/extensions/chaeo/tests/test_zstack.py b/extensions/chaeo/tests/test_zstack.py
index 453ea4b3984f2741f6fb276476aa977d689f936d..53cdac09349611a2e801d2a7d96e5a13056da5d6 100644
--- a/extensions/chaeo/tests/test_zstack.py
+++ b/extensions/chaeo/tests/test_zstack.py
@@ -8,7 +8,7 @@ from extensions.chaeo.conf.testing import multichannel_zstack, pixel_classifier,
 from extensions.chaeo.products import export_patches_from_zstack, export_multichannel_patches_from_zstack, export_patch_masks_from_zstack
 from extensions.chaeo.zmask import build_zmask_from_object_mask
 from model_server.accessors import generate_file_accessor, InMemoryDataAccessor, write_accessor_data_to_file
-from extensions.ilastik.models import IlastikObjectClassifierModel, IlastikPixelClassifierModel
+from extensions.ilastik.models import IlastikPixelClassifierModel
 
 class TestZStackDerivedDataProducts(unittest.TestCase):
 
@@ -57,6 +57,18 @@ class TestZStackDerivedDataProducts(unittest.TestCase):
 
         return zmask, meta
 
+    def test_zmask_works_on_non_zstacks(self, **kwargs):
+        acc_zstack_slice = InMemoryDataAccessor(self.stack.data[:, :, 0, 0])
+        self.assertEqual(acc_zstack_slice.nz, 1)
+        zmask, meta, df, interm = build_zmask_from_object_mask(
+            self.obmap.get_one_channel_data(0),
+            acc_zstack_slice,
+            mask_type='boxes',
+            **kwargs,
+        )
+        zmask_acc = InMemoryDataAccessor(zmask)
+        self.assertTrue(zmask_acc.is_mask())
+
     def test_zmask_makes_correct_contours(self):
         return self.test_zmask_makes_correct_boxes(mask_type='contours')