[ci] [Dask] enable Dask tests on macOS

.vsts-ci.yml

@@ -243,6 +243,8 @@ jobs:
   - script: |
       git clean -d -f -x
     displayName: 'Clean source directory'
+  # LGBM_SKIP_DASK_TESTS=true is set below only because running the tests under emulation is so slow...
+  # in theory, 'lightgbm.dask' should work without issue on aarch64 Linux systems
   - script: |
       cat > docker-script.sh <<EOF
       export CONDA=\$HOME/miniforge
@@ -266,6 +268,7 @@ jobs:
         --env OS_NAME=linux \
         --env PRODUCES_ARTIFACTS=$PRODUCES_ARTIFACTS \
         --env PYTHON_VERSION=$PYTHON_VERSION \
+        --env LGBM_SKIP_DASK_TESTS=true \
         --env TASK=$TASK \
         -v "$(Build.SourcesDirectory)":"$BUILD_DIRECTORY" \
         -v "$(Build.ArtifactStagingDirectory)":"$(Build.ArtifactStagingDirectory)" \

docs/Parallel-Learning-Guide.rst

@@ -64,7 +64,7 @@ LightGBM's Python-package supports distributed learning via `Dask`_. This integr
 
 .. warning::
 
-    Dask integration is only tested on Linux.
+    Dask integration is only tested on macOS and Linux.
 
 Dask Examples
 '''''''''''''

tests/python_package_test/test_dask.py

@@ -6,7 +6,6 @@
 import socket
 from itertools import groupby
 from os import getenv
-from platform import machine
 from sys import platform
 from urllib.parse import urlparse
 
@@ -17,10 +16,8 @@
 
 from .utils import sklearn_multiclass_custom_objective
 
-if not platform.startswith("linux"):
-    pytest.skip("lightgbm.dask is currently supported in Linux environments", allow_module_level=True)
-if machine() != "x86_64":
-    pytest.skip("lightgbm.dask tests are currently skipped on some architectures like arm64", allow_module_level=True)
+if platform in {"cygwin", "win3"}:
+    pytest.skip("lightgbm.dask is not currently supported on Windows", allow_module_level=True)
 if not lgb.compat.DASK_INSTALLED:
     pytest.skip("Dask is not installed", allow_module_level=True)
 
@@ -59,6 +56,10 @@
     pytest.mark.skipif(getenv("TASK", "") == "mpi", reason="Fails to run with MPI interface"),
     pytest.mark.skipif(getenv("TASK", "") == "gpu", reason="Fails to run with GPU interface"),
     pytest.mark.skipif(getenv("TASK", "") == "cuda", reason="Fails to run with CUDA interface"),
+    pytest.mark.skipif(
+        getenv("LGBM_SKIP_DASK_TESTS", "") == "true",
+        reason="Skipping lightgbm.dask tests (found env variable LGBM_SKIP_DASK_TESTS=true)",
+    ),
 ]