ENH: Raise and catch FloatingPointException due to overflow

* Modify tests to only cover windows platforms

Author: sweb

pandas/core/reshape/reshape.py

@@ -130,9 +130,12 @@ def __init__(self, values, index, level=-1, value_columns=None,
         num_rows = np.max([index_level.size for index_level
                            in self.new_index_levels])
         num_columns = self.removed_level.size
-        if num_rows * num_columns > (2 ** 31 - 1):
-            raise ValueError('Unstacked DataFrame is too big, '
-                             'causing int32 overflow')
+        with np.errstate(all='raise'):
+            try:
+                num_columns * num_rows
+            except FloatingPointError:
+                raise ValueError('Unstacked DataFrame is too big, '
+                                 'causing int32 overflow')
 
         self._make_sorted_values_labels()
         self._make_selectors()

pandas/tests/reshape/test_pivot.py

@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 
 from datetime import datetime, date, timedelta
+import sys
 
 import pytest
 
@@ -1279,12 +1280,14 @@ def test_pivot_string_func_vs_func(self, f, f_numpy):
     @pytest.mark.slow
     def test_pivot_number_of_levels_larger_than_int32(self):
         # GH 20601
-        df = DataFrame({'ind1': np.arange(2 ** 16),
-                        'ind2': np.arange(2 ** 16),
-                        'count': np.arange(2 ** 16)})
-        with tm.assert_raises_regex(ValueError, 'int32 overflow'):
-            df.pivot_table(index='ind1', columns='ind2',
-                           values='count', aggfunc='count')
+        if sys.platform == 'win32':
+            df = DataFrame({'ind1': np.arange(2 ** 16),
+                            'ind2': np.arange(2 ** 16),
+                            'count': 0})
+
+            with tm.assert_raises_regex(ValueError, 'int32 overflow'):
+                df.pivot_table(index='ind1', columns='ind2',
+                               values='count', aggfunc='count')
 
 
 class TestCrosstab(object):

pandas/tests/test_multilevel.py

@@ -3,6 +3,8 @@
 from warnings import catch_warnings, simplefilter
 import datetime
 import itertools
+import sys
+
 import pytest
 import pytz
 
@@ -1214,11 +1216,12 @@ def test_unstack_unobserved_keys(self):
 
     @pytest.mark.slow
     def test_unstack_number_of_levels_larger_than_int32(self):
-        # GH 20601
-        df = DataFrame(np.random.randn(2 ** 16, 2),
-                       index=[np.arange(2 ** 16), np.arange(2 ** 16)])
-        with tm.assert_raises_regex(ValueError, 'int32 overflow'):
-            df.unstack()
+        if sys.platform == 'win32':
+            # GH 20601
+            df = DataFrame(np.random.randn(2 ** 16, 2),
+                           index=[np.arange(2 ** 16), np.arange(2 ** 16)])
+            with tm.assert_raises_regex(ValueError, 'int32 overflow'):
+                df.unstack()
 
     def test_stack_order_with_unsorted_levels(self):
         # GH 16323