skip tests if the dependencies are not available (#85)

* add skip decorators for dask, scipy, and bottleneck

* use the decorators

* require dask.array

Author: keewis

pint_xarray/tests/test_accessors.py

@@ -8,7 +8,15 @@
 
 from .. import accessors, conversion
 from ..errors import DimensionalityError
-from .utils import assert_equal, assert_identical, assert_units_equal, raises_regex
+from .utils import (
+    assert_equal,
+    assert_identical,
+    assert_units_equal,
+    raises_regex,
+    requires_bottleneck,
+    requires_dask_array,
+    requires_scipy,
+)
 
 pytestmark = [
     pytest.mark.filterwarnings("error::pint.UnitStrippedWarning"),
@@ -814,6 +822,7 @@ def test_drop_sel(obj, indexers, expected, error):
         assert_identical(actual, expected)
 
 
+@requires_dask_array
 @pytest.mark.parametrize(
     "obj",
     (
@@ -1144,6 +1153,7 @@ def test_reindex_like(obj, other, expected, error):
         assert_identical(actual, expected)
 
 
+@requires_scipy
 @pytest.mark.parametrize(
     ["obj", "indexers", "expected", "error"],
     (
@@ -1307,6 +1317,7 @@ def test_interp(obj, indexers, expected, error):
         assert_identical(actual, expected)
 
 
+@requires_scipy
 @pytest.mark.parametrize(
     ["obj", "other", "expected", "error"],
     (
@@ -1504,6 +1515,7 @@ def test_interp_like(obj, other, expected, error):
         assert_identical(actual, expected)
 
 
+@requires_bottleneck
 @pytest.mark.parametrize(
     ["obj", "expected"],
     (
@@ -1598,6 +1610,7 @@ def test_ffill(obj, expected):
     assert_units_equal(actual, expected)
 
 
+@requires_bottleneck
 @pytest.mark.parametrize(
     ["obj", "expected"],
     (

pint_xarray/tests/utils.py

@@ -16,6 +16,21 @@
 )
 
 
+def importorskip(name):
+    try:
+        __import__(name)
+        has_name = True
+    except ImportError:
+        has_name = False
+
+    return has_name, pytest.mark.skipif(not has_name, reason=f"{name} is not available")
+
+
+has_dask_array, requires_dask_array = importorskip("dask.array")
+has_scipy, requires_scipy = importorskip("scipy")
+has_bottleneck, requires_bottleneck = importorskip("bottleneck")
+
+
 @contextmanager
 def raises_regex(error, pattern):
     __tracebackhide__ = True