Update Dask Tests

holoviews/tests/core/data/test_daskinterface.py

@@ -13,13 +13,10 @@
 from holoviews.core.util import PANDAS_VERSION
 from holoviews.util.transform import dim
 
-from ...utils import dask_switcher
+from ...utils import DASK_VERSION, dask_setup, dask_switcher
 from .test_pandasinterface import BasePandasInterfaceTests
 
-try:
-    import dask_expr
-except ImportError:
-    dask_expr = None
+classic, expr = dask_setup()
 
 
 class _DaskDatasetTest(BasePandasInterfaceTests):
@@ -136,9 +133,11 @@ def test_select_expression_lazy(self):
 
 class DaskClassicDatasetTest(_DaskDatasetTest):
 
-    data_type = dd.core.DataFrame
+    # No longer supported from Dask 2025.1
 
-    __test__ = True
+    data_type = getattr(dd.core, "DataFrame", None)
+
+    __test__ = classic
 
     @dask_switcher(query=False)
     def setUp(self):
@@ -147,11 +146,17 @@ def setUp(self):
 
 class DaskExprDatasetTest(_DaskDatasetTest):
 
-    __test__ = bool(dask_expr)
+    __test__ = expr
 
     @property
     def data_type(self):
-        return dask_expr.DataFrame
+        # Only available from 2025.1 and forward
+        if DASK_VERSION >= (2025, 1, 0):
+            return dd.DataFrame
+        else:
+            import dask_expr
+
+            return dask_expr.DataFrame
 
     @dask_switcher(query=True)
     def setUp(self):

holoviews/tests/utils.py

@@ -8,8 +8,8 @@
 
 import param
 import pytest
-from packaging.version import Version
 
+from holoviews.core.util import _no_import_version
 from holoviews.element.comparison import ComparisonTestCase
 
 cwd = os.path.abspath(os.path.split(__file__)[0])
@@ -120,21 +120,21 @@ def tearDown(self):
 
 
 DASK_UNAVAILABLE = find_spec("dask") is None
+DASK_VERSION = _no_import_version("dask")
 
 
 @lru_cache
-def _dask_setup():
+def dask_setup():
     """
     Set-up both dask dataframes, using lru_cahce to only do it once
 
     """
-    import dask
     from datashader.data_libraries.dask import bypixel, dask_pipeline
 
     classic, expr = False, False
 
     # Removed in Dask 2025.1, and will raise AttributeError
-    if Version(dask.__version__).release < (2025, 1, 0):
+    if DASK_VERSION < (2025, 1, 0):
         import dask.dataframe as dd
 
         bypixel.pipeline.register(dd.core.DataFrame)(dask_pipeline)
@@ -164,7 +164,7 @@ def dask_switcher(*, query=False, extras=None):
     if DASK_UNAVAILABLE:
         pytest.skip("dask is not available")
 
-    classic, expr = _dask_setup()
+    classic, expr = dask_setup()
 
     if not query and not classic:
         pytest.skip("Classic DataFrame no longer supported by dask")