diff --git a/requirements/requirements-test.txt b/requirements/requirements-test.txt
index 098e5ae..54a46f7 100644
--- a/requirements/requirements-test.txt
+++ b/requirements/requirements-test.txt
@@ -1,4 +1,4 @@
 coverage==7.4.3
-pytest==7.4.4
+pytest==8.0.2
 pytest-cov==4.1.0
 pytest-xdist==3.5.0
diff --git a/synced_collections/numpy_utils.py b/synced_collections/numpy_utils.py
index 1ba37c4..0ef141c 100644
--- a/synced_collections/numpy_utils.py
+++ b/synced_collections/numpy_utils.py
@@ -84,11 +84,11 @@ def _is_numpy_scalar(data):
 def _is_complex(data):
     """Check if an object is complex.
 
-    This function works for both numpy raw Python data types.
+    This function works for numpy arrays, scalars, and raw Python data types.
 
     Returns
     -------
     bool
         Whether or not the input is a complex number.
     """
-    return (NUMPY and numpy.iscomplex(data).any()) or (isinstance(data, complex))
+    return (NUMPY and numpy.iscomplexobj(data)) or isinstance(data, complex)
diff --git a/tests/synced_collection_test.py b/tests/synced_collection_test.py
index 1fab325..c64efd5 100644
--- a/tests/synced_collection_test.py
+++ b/tests/synced_collection_test.py
@@ -3,12 +3,14 @@
 # This software is licensed under the BSD 3-Clause License.
 import platform
 from collections.abc import MutableMapping, MutableSequence
+from contextlib import nullcontext
 from copy import deepcopy
 from typing import Any, Tuple, Type
 
 import pytest
 
 from synced_collections import SyncedCollection
+from synced_collections.backends.collection_zarr import ZarrCollection
 from synced_collections.errors import KeyTypeError
 from synced_collections.numpy_utils import NumpyConversionWarning
 
@@ -526,15 +528,16 @@ def test_set_get_numpy_float_data(self, synced_collection, dtype, shape):
         # should fail to set correctly.
         raw_value = value.item() if shape is None else value.tolist()
         test_value = value.item(0) if isinstance(raw_value, list) else raw_value
-        has_corresponding_python_type = isinstance(
-            test_value, (numpy.number, numpy.bool_)
-        )
+        should_fail = isinstance(test_value, (numpy.number, numpy.bool_))
 
-        if has_corresponding_python_type:
-            with pytest.raises((ValueError, TypeError)), pytest.warns(
-                NumpyConversionWarning
-            ):
-                synced_collection["numpy_dtype_val"] = value
+        maybe_warn = nullcontext()
+        if isinstance(synced_collection, ZarrCollection):
+            maybe_warn = pytest.warns(NumpyConversionWarning)
+
+        if should_fail:
+            with pytest.raises((ValueError, TypeError)):
+                with maybe_warn:
+                    synced_collection["numpy_dtype_val"] = value
         else:
             with pytest.warns(NumpyConversionWarning):
                 synced_collection["numpy_dtype_val"] = value
@@ -553,10 +556,13 @@ def test_set_get_numpy_complex_data(self, synced_collection, dtype, shape):
         # not a priority to test here).
         value = dtype(random_sample(shape))
 
-        with pytest.raises((ValueError, TypeError)), pytest.warns(
-            NumpyConversionWarning
-        ):
-            synced_collection["numpy_dtype_val"] = value
+        maybe_warn = nullcontext()
+        if isinstance(synced_collection, ZarrCollection):
+            maybe_warn = pytest.warns(NumpyConversionWarning)
+
+        with pytest.raises((ValueError, TypeError)):
+            with maybe_warn:
+                synced_collection["numpy_dtype_val"] = value
 
 
 class SyncedListTest(SyncedCollectionTest):
@@ -813,11 +819,14 @@ def test_set_get_numpy_float_data(self, synced_collection, dtype, shape):
         test_value = value.item(0) if isinstance(raw_value, list) else raw_value
         should_fail = isinstance(test_value, (numpy.number, numpy.bool_))
 
+        maybe_warn = nullcontext()
+        if isinstance(synced_collection, ZarrCollection):
+            maybe_warn = pytest.warns(NumpyConversionWarning)
+
         if should_fail:
-            with pytest.raises((ValueError, TypeError)), pytest.warns(
-                NumpyConversionWarning
-            ):
-                synced_collection.append(value)
+            with pytest.raises((ValueError, TypeError)):
+                with maybe_warn:
+                    synced_collection.append(value)
         else:
             with pytest.warns(NumpyConversionWarning):
                 synced_collection.append(value)
@@ -840,14 +849,15 @@ def test_set_get_numpy_complex_data(self, synced_collection, dtype, shape):
         # not a priority to test here).
         value = dtype(random_sample(shape))
 
-        with pytest.raises((ValueError, TypeError)), pytest.warns(
-            NumpyConversionWarning
-        ):
-            synced_collection.append(value)
+        maybe_warn = nullcontext()
+        if isinstance(synced_collection, ZarrCollection):
+            maybe_warn = pytest.warns(NumpyConversionWarning)
+
+        with pytest.raises((ValueError, TypeError)):
+            with maybe_warn:
+                synced_collection.append(value)
 
-        with pytest.raises((ValueError, TypeError)), pytest.warns(
-            NumpyConversionWarning
-        ):
+        with pytest.raises((ValueError, TypeError)):
             synced_collection[-1] = value
 
     @pytest.mark.parametrize("dtype", NUMPY_INT_TYPES)