From 62edbe44892d10d199393eae3f6c7645a2689ea4 Mon Sep 17 00:00:00 2001
From: Matthew Avaylon <mavaylon1@berkeley.edu>
Date: Fri, 5 Jul 2024 12:40:28 -0700
Subject: [PATCH] Make Zarr optional for testing (#1141)

---
 pyproject.toml                           |  1 -
 src/hdmf/data_utils.py                   | 13 ++++++++----
 tests/unit/utils_test/test_data_utils.py | 25 +++++++++++++++++++++++-
 3 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/pyproject.toml b/pyproject.toml
index a089113c0..6ef9850a6 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -36,7 +36,6 @@ dependencies = [
     "pandas>=1.0.5",
     "ruamel.yaml>=0.16",
     "scipy>=1.4",
-    "zarr >= 2.12.0",
     "importlib-resources; python_version < '3.9'",  # TODO: remove when minimum python version is 3.9
 ]
 dynamic = ["version"]
diff --git a/src/hdmf/data_utils.py b/src/hdmf/data_utils.py
index 71f5bdf6d..798a40973 100644
--- a/src/hdmf/data_utils.py
+++ b/src/hdmf/data_utils.py
@@ -5,7 +5,12 @@
 from warnings import warn
 from typing import Tuple
 from itertools import product, chain
-from zarr import Array as ZarrArray
+
+try:
+    from zarr import Array as ZarrArray
+    ZARR_INSTALLED = True
+except ImportError:
+    ZARR_INSTALLED = False
 
 import h5py
 import numpy as np
@@ -16,9 +21,6 @@ def append_data(data, arg):
     if isinstance(data, (list, DataIO)):
         data.append(arg)
         return data
-    elif isinstance(data, ZarrArray):
-        data.append([arg], axis=0)
-        return data
     elif type(data).__name__ == 'TermSetWrapper': # circular import
         data.append(arg)
         return data
@@ -33,6 +35,9 @@ def append_data(data, arg):
         data.resize(shape)
         data[-1] = arg
         return data
+    elif ZARR_INSTALLED and isinstance(data, ZarrArray):
+        data.append([arg], axis=0)
+        return data
     else:
         msg = "Data cannot append to object of type '%s'" % type(data)
         raise ValueError(msg)
diff --git a/tests/unit/utils_test/test_data_utils.py b/tests/unit/utils_test/test_data_utils.py
index 2e0df7ba8..b5a5e50e7 100644
--- a/tests/unit/utils_test/test_data_utils.py
+++ b/tests/unit/utils_test/test_data_utils.py
@@ -3,9 +3,32 @@
 
 import numpy as np
 from numpy.testing import assert_array_equal
-import zarr
+
+try:
+    import zarr
+    ZARR_INSTALLED = True
+except ImportError:
+    ZARR_INSTALLED = False
+
+
+class MyIterable:
+    def __init__(self, data):
+        self.data = data
+
 
 class TestAppendData(TestCase):
+    def test_append_exception(self):
+        data = MyIterable([1, 2, 3, 4, 5])
+        with self.assertRaises(ValueError):
+            append_data(data, 4)
+
+
+class TestZarrAppendData(TestCase):
+
+    def setUp(self):
+        if not ZARR_INSTALLED:
+            self.skipTest("optional Zarr package is not installed")
+
 
     def test_append_data_zarr(self):
         zarr_array = zarr.array([1,2,3])