clarified according to comments

pandas/conftest.py

@@ -6,7 +6,7 @@
 import pandas
 import numpy as np
 import pandas as pd
-from pandas.compat import PY3, PY36
+from pandas.compat import PY3
 import pandas.util._test_decorators as td
 
 
@@ -69,6 +69,9 @@ def axis(request):
     return request.param
 
 
+axis_frame = axis
+
+
 @pytest.fixture(params=[0, 'index'], ids=lambda x: "axis {!r}".format(x))
 def axis_series(request):
     """
@@ -120,18 +123,41 @@ def all_arithmetic_operators(request):
     return request.param
 
 
-_cython_table = list(pd.core.base.SelectionMixin._cython_table.items())
-if not PY36:
-    # dicts have random order in Python<3.6, which xdist doesn't like
-    _cython_table = sorted(((key, value) for key, value in _cython_table),
-                           key=lambda x: x[0].__class__.__name__)
+# use sorted as dicts in py<3.6 have random order, which xdist doesn't like
+_cython_table = sorted(((key, value) for key, value in
+                        pd.core.base.SelectionMixin._cython_table.items()),
+                       key=lambda x: x[0].__class__.__name__)
 
 
 @pytest.fixture(params=_cython_table)
 def cython_table_items(request):
     return request.param
 
 
+def _get_cython_table_params(ndframe, func_names_and_expected):
+    """combine frame, functions from SelectionMixin._cython_table
+    keys and expected result.
+
+    Parameters
+    ----------
+    ndframe : DataFrame or Series
+    func_names_and_expected : Sequence of two items
+        The first item is a name of a NDFrame method ('sum', 'prod') etc.
+        The second item is the expected return value
+
+    Returns
+    -------
+    results : list
+        List of three items (DataFrame, function, expected result)
+    """
+    results = []
+    for func_name, expected in func_names_and_expected:
+        results.append((ndframe, func_name, expected))
+        results += [(ndframe, func, expected) for func, name in _cython_table
+                    if name == func_name]
+    return results
+
+
 @pytest.fixture(params=['__eq__', '__ne__', '__le__',
                         '__lt__', '__ge__', '__gt__'])
 def all_compare_operators(request):

pandas/core/frame.py

@@ -6080,8 +6080,9 @@ def aggregate(self, func, axis=0, *args, **kwargs):
         return result
 
     def _aggregate(self, arg, axis=0, *args, **kwargs):
-        axis = self._get_axis_number(axis)
         if axis == 1:
+            # NDFrame.aggregate returns a tuple, and we need to transpose
+            # only result
             result, how = (super(DataFrame, self.T)
                            ._aggregate(arg, *args, **kwargs))
             result = result.T if result is not None else result
@@ -6090,6 +6091,7 @@ def _aggregate(self, arg, axis=0, *args, **kwargs):
 
     agg = aggregate
 
+    @Appender(_shared_docs['transform'] % _shared_doc_kwargs)
     def transform(self, func, axis=0, *args, **kwargs):
         axis = self._get_axis_number(axis)
         if axis == 1:

pandas/tests/frame/test_apply.py

@@ -20,35 +20,10 @@
 from pandas.util.testing import (assert_series_equal,
                                  assert_frame_equal)
 import pandas.util.testing as tm
+from pandas.conftest import _get_cython_table_params
 from pandas.tests.frame.common import TestData
 
 
-def _get_cython_table_params(frame, func_names_and_expected):
-    """combine frame, functions from SelectionMixin._cython_table
-    keys and expected result.
-
-    Parameters
-    ----------
-    frame : DataFrame
-        A symmetrical DataFrame
-    func_names_and_expected : Sequence of two items
-        The first item is a name of a NDFrame method ('sum', 'prod') etc.
-        The second item is the expected return value
-
-    Returns
-    -------
-    results : list
-        List of three items (DataFrame, function, expected result)
-    """
-    from pandas.conftest import _cython_table
-    results = []
-    for func_name, expected in func_names_and_expected:
-        results.append((frame, func_name, expected))
-        results += [(frame, func, expected) for func, name in _cython_table
-                    if name == func_name]
-    return results
-
-
 class TestDataFrameApply(TestData):
 
     def test_apply(self):

pandas/tests/series/test_apply.py

@@ -12,39 +12,14 @@
 from pandas import (Index, Series, DataFrame, isna)
 from pandas.compat import lrange
 from pandas import compat
-from pandas.util.testing import assert_series_equal, assert_frame_equal
+from pandas.util.testing import (assert_series_equal,
+                                 assert_frame_equal)
 import pandas.util.testing as tm
+from pandas.conftest import _get_cython_table_params
 
 from .common import TestData
 
 
-def _get_cython_table_params(series, func_names_and_expected):
-    """combine series, functions from SelectionMixin._cython_table
-    keys and expected result.
-
-    Parameters
-    ----------
-    series : Series
-        A Series
-    func_names_and_expected : Sequence of two items
-        The first item is a name of a NDFrame method ('sum', 'prod') etc.
-        The second item is the expected return value
-
-    Returns
-    -------
-    results : list
-        List of three items (Series, function, expected result)
-    """
-    from pandas.conftest import _cython_table
-    results = []
-    for func_name, expected in func_names_and_expected:
-        results.append((series, func_name, expected))
-        results += [
-            (series, func, expected) for func, name in _cython_table
-            if name == func_name]
-    return results
-
-
 class TestSeriesApply(TestData):
 
     def test_apply(self):