Skip tests safely without sparse installed

genno/tests/core/test_sparsedataarray.py

@@ -4,17 +4,16 @@
 import numpy as np
 import pandas as pd
 import pytest
-import sparse
 import xarray as xr
 from xarray.testing import assert_equal as assert_xr_equal
 
 import genno
 from genno import Computer
-from genno.core.sparsedataarray import HAS_SPARSE, SparseDataArray
+from genno.core.sparsedataarray import SparseDataArray
 from genno.testing import add_test_data, random_qty
 
-pytestmark = pytest.mark.skipif(
-    condition=not HAS_SPARSE,
+sparse = pytest.importorskip(
+    "sparse",
     reason="`sparse` not available → can't test SparseDataArray",
 )
 

genno/tests/test_caching.py

@@ -9,7 +9,7 @@
 import genno.caching
 from genno.caching import Encoder, decorate, hash_args, hash_code, hash_contents
 from genno.core.attrseries import AttrSeries
-from genno.core.sparsedataarray import SparseDataArray
+from genno.core.sparsedataarray import HAS_SPARSE, SparseDataArray
 
 
 class TestEncoder:
@@ -58,11 +58,19 @@ def _serialize_bar(o: Bar):
 @pytest.mark.parametrize(
     "value, suffix",
     (
-        (np.array([3]), "pickle"),
-        (pd.DataFrame(), "parquet"),
-        (AttrSeries(), "parquet" if sys.version_info >= (3, 9) else "pickle"),
+        (lambda: np.array([3]), "pickle"),
+        (pd.DataFrame, "parquet"),
+        (AttrSeries, "parquet" if sys.version_info >= (3, 9) else "pickle"),
         pytest.param(
-            SparseDataArray(), "parquet", marks=pytest.mark.xfail(raises=TypeError)
+            SparseDataArray,
+            "parquet",
+            marks=[
+                pytest.mark.skipif(
+                    not HAS_SPARSE,
+                    reason="`sparse` not available → can't test SparseDataArray",
+                ),
+                pytest.mark.xfail(raises=TypeError),
+            ],
         ),
     ),
 )
@@ -72,12 +80,12 @@ def test_decorate(caplog, tmp_path, value, suffix):
     caplog.set_level(logging.DEBUG)
 
     def myfunc():
-        return value
+        return value()
 
     decorated = decorate(myfunc, cache_path=tmp_path)
 
     # Decorated function runs
-    assert all(value == decorated())
+    assert all(value() == decorated())
 
     # Value was cached
     # NB use [1] not [-1] to accommodate a possible message about Parquet support
@@ -86,7 +94,7 @@ def myfunc():
     assert 1 == len(files)
 
     # Cache hit on the second call
-    assert all(value == decorated())
+    assert all(value() == decorated())
     assert caplog.messages[-1].startswith("Cache hit for myfunc(<")
 
     for f in files: