COMPAT: windows compat for tests for dtype inference in parser xref (GH8833)

Author: jreback

pandas/io/tests/test_parsers.py

@@ -3173,8 +3173,9 @@ def test_dtype_and_names_error(self):
         tm.assert_frame_equal(result, expected)
 
         # fallback casting
-        result = self.read_csv(StringIO(data),sep='\s+',header=None,names=['a','b'],dtype={'a' : int})
+        result = self.read_csv(StringIO(data),sep='\s+',header=None,names=['a','b'],dtype={'a' : np.int32})
         expected = DataFrame([[1,1],[2,2],[3,3]],columns=['a','b'])
+        expected['a'] = expected['a'].astype(np.int32)
         tm.assert_frame_equal(result, expected)
 
         data = """
@@ -3184,7 +3185,7 @@ def test_dtype_and_names_error(self):
 """
         # fallback casting, but not castable
         with tm.assertRaisesRegexp(ValueError, 'cannot safely convert'):
-            self.read_csv(StringIO(data),sep='\s+',header=None,names=['a','b'],dtype={'a' : int})
+            self.read_csv(StringIO(data),sep='\s+',header=None,names=['a','b'],dtype={'a' : np.int32})
 
     def test_fallback_to_python(self):
         # GH 6607

pandas/parser.pyx

@@ -1060,7 +1060,7 @@ cdef class TextReader:
                 if na_count > 0:
                     raise Exception('Integer column has NA values')
 
-            if dtype[1:] != 'i8':
+            if result is not None and dtype[1:] != 'i8':
                 result = result.astype(dtype)
 
             return result, na_count
@@ -1069,7 +1069,7 @@ cdef class TextReader:
             result, na_count = _try_double(self.parser, i, start, end,
                           na_filter, na_hashset, na_flist)
 
-            if dtype[1:] != 'f8':
+            if result is not None and dtype[1:] != 'f8':
                 result = result.astype(dtype)
             return result, na_count