xfail tests that append to netCDF files with scipy (#2021)

* xfail tests that append to netCDF files with scipy

These are broken by SciPy 1.0.1.

For details, see #2019

* xfail pynio tests that use scipy too

Author: shoyer

xarray/tests/test_backends.py

@@ -1404,8 +1404,23 @@ def create_zarr_target(self):
             yield tmp
 
 
+class ScipyWriteTest(CFEncodedDataTest, NetCDF3Only):
+
+    def test_append_write(self):
+        import scipy
+        if scipy.__version__ == '1.0.1':
+            pytest.xfail('https://github.com/scipy/scipy/issues/8625')
+        super(ScipyWriteTest, self).test_append_write()
+
+    def test_append_overwrite_values(self):
+        import scipy
+        if scipy.__version__ == '1.0.1':
+            pytest.xfail('https://github.com/scipy/scipy/issues/8625')
+        super(ScipyWriteTest, self).test_append_overwrite_values()
+
+
 @requires_scipy
-class ScipyInMemoryDataTest(CFEncodedDataTest, NetCDF3Only, TestCase):
+class ScipyInMemoryDataTest(ScipyWriteTest, TestCase):
     engine = 'scipy'
 
     @contextlib.contextmanager
@@ -1431,7 +1446,7 @@ class ScipyInMemoryDataTestAutocloseTrue(ScipyInMemoryDataTest):
 
 
 @requires_scipy
-class ScipyFileObjectTest(CFEncodedDataTest, NetCDF3Only, TestCase):
+class ScipyFileObjectTest(ScipyWriteTest, TestCase):
     engine = 'scipy'
 
     @contextlib.contextmanager
@@ -1459,7 +1474,7 @@ def test_pickle_dataarray(self):
 
 
 @requires_scipy
-class ScipyFilePathTest(CFEncodedDataTest, NetCDF3Only, TestCase):
+class ScipyFilePathTest(ScipyWriteTest, TestCase):
     engine = 'scipy'
 
     @contextlib.contextmanager
@@ -2168,7 +2183,7 @@ def test_session(self):
 
 @requires_scipy
 @requires_pynio
-class TestPyNio(CFEncodedDataTest, NetCDF3Only, TestCase):
+class PyNioTest(ScipyWriteTest, TestCase):
     def test_write_store(self):
         # pynio is read-only for now
         pass
@@ -2194,7 +2209,7 @@ def test_weakrefs(self):
             assert_identical(actual, expected)
 
 
-class TestPyNioAutocloseTrue(TestPyNio):
+class PyNioTestAutocloseTrue(PyNioTest):
     autoclose = True