BLD/TST: cross compat for pa/fp failing on osx & windows

xref #18662

Author: jreback

ci/requirements-3.5_OSX.sh

@@ -4,4 +4,4 @@ source activate pandas
 
 echo "install 35_OSX"
 
-conda install -n pandas -c conda-forge feather-format==0.3.1 fastparquet
+conda install -n pandas -c conda-forge feather-format==0.3.1 fastparquet pyarrow

pandas/tests/io/test_parquet.py

@@ -7,7 +7,7 @@
 
 import numpy as np
 import pandas as pd
-from pandas.compat import PY3, is_platform_windows
+from pandas import compat
 from pandas.io.parquet import (to_parquet, read_parquet, get_engine,
                                PyArrowImpl, FastParquetImpl)
 from pandas.util import testing as tm
@@ -174,8 +174,7 @@ def test_options_get_engine(fp, pa):
         assert isinstance(get_engine('fastparquet'), FastParquetImpl)
 
 
-@pytest.mark.xfail(is_platform_windows(),
-                   reason="reading pa metadata failing on Windows")
+@pytest.mark.xfail(reason="reading pa metadata failing")
 def test_cross_engine_pa_fp(df_cross_compat, pa, fp):
     # cross-compat with differing reading/writing engines
 
@@ -263,7 +262,7 @@ def test_columns_dtypes_invalid(self, engine):
         df.columns = [0, 1]
         self.check_error_on_write(df, engine, ValueError)
 
-        if PY3:
+        if compat.PY3:
             # bytes on PY3, on PY2 these are str
             df.columns = [b'foo', b'bar']
             self.check_error_on_write(df, engine, ValueError)