simple test classes for creation and reduction (#2)

* first draft of the variable creation tests

* reduction tests

* missing test dependency

* also allow python 3.11

* remove left-over class attribute

* move the configuration hooks to a abstract base class

* typing

Author: keewis

ci/requirements/environment.yaml

@@ -2,11 +2,11 @@ name: xarray-array-testing-tests
 channels:
   - conda-forge
 dependencies:
-  - python=3.12
   - ipython
   - pre-commit
   - pytest
   - pytest-reportlog
+  - pytest-cov
   - hypothesis
   - xarray
   - numpy

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "xarray-array-testing"
-requires-python = ">= 3.12"
+requires-python = ">= 3.11"
 license = {text = "Apache-2.0"}
 dependencies = [
     "hypothesis",
@@ -51,7 +51,7 @@ ignore = [
     "E501", # E501: line too long - let black worry about that
     "E731", # E731: do not assign a lambda expression, use a def
 ]
-fixable = ["I"]
+fixable = ["I", "TID"]
 extend-safe-fixes = [
     "TID252",  # absolute imports
 ]

xarray_array_testing/base.py

@@ -0,0 +1,27 @@
+import abc
+from abc import ABC
+from types import ModuleType
+
+import numpy.testing as npt
+from xarray.namedarray._typing import duckarray
+
+
+class DuckArrayTestMixin(ABC):
+    @property
+    @abc.abstractmethod
+    def xp() -> ModuleType:
+        pass
+
+    @property
+    @abc.abstractmethod
+    def array_type(self) -> type[duckarray]:
+        pass
+
+    @staticmethod
+    @abc.abstractmethod
+    def array_strategy_fn(*, shape, dtype):
+        raise NotImplementedError("has to be overridden")
+
+    @staticmethod
+    def assert_equal(a, b):
+        npt.assert_equal(a, b)

xarray_array_testing/creation.py

@@ -0,0 +1,13 @@
+import hypothesis.strategies as st
+import xarray.testing.strategies as xrst
+from hypothesis import given
+
+from xarray_array_testing.base import DuckArrayTestMixin
+
+
+class CreationTests(DuckArrayTestMixin):
+    @given(st.data())
+    def test_create_variable(self, data):
+        variable = data.draw(xrst.variables(array_strategy_fn=self.array_strategy_fn))
+
+        assert isinstance(variable.data, self.array_type)

xarray_array_testing/reduction.py

@@ -0,0 +1,33 @@
+from contextlib import nullcontext
+
+import hypothesis.strategies as st
+import xarray.testing.strategies as xrst
+from hypothesis import given
+
+from xarray_array_testing.base import DuckArrayTestMixin
+
+
+class ReductionTests(DuckArrayTestMixin):
+    @staticmethod
+    def expected_errors(op, **parameters):
+        return nullcontext()
+
+    @given(st.data())
+    def test_variable_mean(self, data):
+        variable = data.draw(xrst.variables(array_strategy_fn=self.array_strategy_fn))
+
+        with self.expected_errors("mean", variable=variable):
+            actual = variable.mean().data
+            expected = self.xp.mean(variable.data)
+
+        self.assert_equal(actual, expected)
+
+    @given(st.data())
+    def test_variable_prod(self, data):
+        variable = data.draw(xrst.variables(array_strategy_fn=self.array_strategy_fn))
+
+        with self.expected_errors("prod", variable=variable):
+            actual = variable.prod().data
+            expected = self.xp.prod(variable.data)
+
+        self.assert_equal(actual, expected)

xarray_array_testing/tests/test_numpy.py

@@ -0,0 +1,34 @@
+from types import ModuleType
+
+import hypothesis.strategies as st
+import numpy as np
+
+from xarray_array_testing.base import DuckArrayTestMixin
+from xarray_array_testing.creation import CreationTests
+from xarray_array_testing.reduction import ReductionTests
+
+
+def create_numpy_array(*, shape, dtype):
+    return st.builds(np.ones, shape=st.just(shape), dtype=st.just(dtype))
+
+
+class NumpyTestMixin(DuckArrayTestMixin):
+    @property
+    def xp(self) -> ModuleType:
+        return np
+
+    @property
+    def array_type(self) -> type[np.ndarray]:
+        return np.ndarray
+
+    @staticmethod
+    def array_strategy_fn(*, shape, dtype):
+        return create_numpy_array(shape=shape, dtype=dtype)
+
+
+class TestCreationNumpy(CreationTests, NumpyTestMixin):
+    pass
+
+
+class TestReductionNumpy(ReductionTests, NumpyTestMixin):
+    pass