using pytest.mark.skipif inside parameters

wabu · wabu · commit 28c0cf5d48e8 · 2016-04-15T14:32:30.000+02:00
diff --git a/conftest.py b/conftest.py
@@ -1,7 +1,5 @@
 import pytest
 
-from dask.compatibility import BZ2File, GzipFile, LZMAFile
-
 
 def pytest_addoption(parser):
     parser.addoption("--runslow", action="store_true", help="run slow tests")
@@ -15,22 +13,3 @@ def pytest_runtest_setup(item):
 def pytest_ignore_collect(path, config):
     if 'run_test.py' in str(path):
         return True
-
-
-@pytest.fixture(params=[(open, None), (GzipFile, 'gzip'),
-                        (BZ2File, 'bz2'), (LZMAFile, 'xz')])
-def open_comp_pair(request):
-    myopen, compression = request.param
-    if compression == 'xz':
-        pytest.importorskip('lzma')
-    return myopen, compression
-
-
-@pytest.fixture
-def myopen(open_comp_pair):
-    return open_comp_pair[0]
-
-
-@pytest.fixture
-def compression(open_comp_pair):
-    return open_comp_pair[1]
diff --git a/dask/compatibility.py b/dask/compatibility.py
@@ -9,6 +9,8 @@
 PY3 = sys.version_info[0] == 3
 PY2 = sys.version_info[0] == 2
 
+LZMA_AVAILABLE = True
+
 if PY3:
     import builtins
     from queue import Queue, Empty
@@ -183,6 +185,7 @@ class LZMAFile:
             def __init__(self, *args, **kwargs):
                 raise ValueError("xz files requires the lzma module. "
                                  "To use, install lzmaffi or backports.lzma.")
+        LZMA_AVAILABLE = False
 
 
 def getargspec(func):
diff --git a/dask/dataframe/tests/test_io.py b/dask/dataframe/tests/test_io.py
@@ -18,7 +18,7 @@
 import dask.dataframe as dd
 from dask.dataframe.io import (read_csv, file_size,  dataframe_from_ctable,
                                from_array, from_bcolz, from_dask_array)
-from dask.compatibility import StringIO, BZ2File, GzipFile, LZMAFile
+from dask.compatibility import BZ2File, GzipFile, LZMAFile, LZMA_AVAILABLE
 
 from dask.utils import filetext, tmpfile, ignoring, compressions
 from dask.async import get_sync
@@ -48,15 +48,25 @@
 """.strip()
 
 
-@pytest.fixture
-def pd_compression(compression):
-    if compression == 'xz' and LooseVersion(pd.__version__) <= '0.18.1':
-        pytest.skip('pandas <= 0.18.0 does not support xz compression')
-    return compression
-
-
-@pytest.mark.parametrize('infer', [True, False])
-def test_read_csv(myopen, compression, pd_compression, infer):
+SKIP_PD_XZ = pytest.mark.skipif(
+    not LZMA_AVAILABLE or LooseVersion(pd.__version__) <= LooseVersion('0.18.0'),
+    reason=('no lzma module found' if not LZMA_AVAILABLE else
+            'pandas <= 0.18.0 does not support xz compression'))
+
+
+@pytest.mark.parametrize('open_comp_pair,infer',
+                         [SKIP_PD_XZ(((o, c), i)) if c == 'xz' else ((o, c), i)
+                          for (o, c), i in product([(open, None),
+                                                    (GzipFile, 'gzip'),
+                                                    (BZ2File, 'bz2'),
+                                                    (LZMAFile, 'xz')],
+                                                   (True, False))])
+def test_read_csv(open_comp_pair, infer):
+    myopen, compression = open_comp_pair
+    if compression == 'xz':
+        if LooseVersion(pd.__version__) <= '0.18.0':
+            pytest.skip()
+        pytest.importorskip('lzma')
     text_ = text if compression is None else text.encode()
     ext = dict((v, k) for (k, v) in compressions.items()).get(compression, '')
     with filetext(text_, open=myopen, extension=ext) as fn:
@@ -69,8 +79,8 @@ def test_read_csv(myopen, compression, pd_compression, infer):
         result = f.compute(get=dask.get)
         # index may be different
         assert eq(result.reset_index(drop=True),
-                  pd.read_csv(fn, compression=pd_compression,
-                              lineterminator='\n'))
+                  pd.read_csv(fn, compression=compression, lineterminator='\n'))
+
 
 
 def test_file_size():
diff --git a/dask/tests/test_utils.py b/dask/tests/test_utils.py
@@ -3,11 +3,18 @@
 import numpy as np
 import pytest
 
+from dask.compatibility import BZ2File, GzipFile, LZMAFile, LZMA_AVAILABLE
 from dask.utils import (textblock, filetext, takes_multiple_arguments,
                         Dispatch, tmpfile, different_seeds, file_size)
 
 
+SKIP_XZ = pytest.mark.skipif(not LZMA_AVAILABLE, reason="no lzma library")
+@pytest.mark.parametrize('myopen,compression',
+                         [(open, None), (GzipFile, 'gzip'), (BZ2File, 'bz2'),
+                          SKIP_XZ((LZMAFile, 'xz'))])
 def test_textblock(myopen, compression):
+    if compression == 'xz':
+        pytest.importorskip('lzma')
     text = b'123 456 789 abc def ghi'.replace(b' ', os.linesep.encode())
     with filetext(text, open=myopen, mode='wb') as fn:
         text = ''.join(textblock(fn, 1, 11, compression)).encode()
@@ -19,6 +26,8 @@ def test_textblock(myopen, compression):
         assert ''.join(textblock(fn, k, k, compression)).encode() == b''
 
 
+@pytest.mark.parametrize('myopen,compression',
+                         [(open, None), (GzipFile, 'gzip'), (BZ2File, 'bz2'), (LZMAFile, 'xz')])
 def test_filesize(myopen, compression):
     if compression == 'xz':
         pytest.importorskip('lzma')
