tests added for pandas-devgh-14671, expected behavior of simultaneous…

… use of usecols and names unclear so these tests are commented out
bpraggastis · Jun 4, 2017 · 1968a70 · 1968a70
1 parent 812f928
commit 1968a70
Showing 1 changed file with 29 additions and 3 deletions.
diff --git a/pandas/tests/io/parser/usecols.py b/pandas/tests/io/parser/usecols.py
@@ -478,18 +478,44 @@ def test_uneven_length_cols(self):
         tm.assert_frame_equal(df, expected)
 
     def test_raise_on_usecols_names_mismatch(self):
-        # see gh-14671
+        ## see gh-14671
         data = 'a,b,c,d\n1,2,3,4\n5,6,7,8'
+        msg = 'Usecols do not match names'  ## from parsers.py CParserWrapper()
+        msg2 = 'is not in list' ## from parser.py _handle_usecols()
+
         usecols = ['a','b','c','d']
         df = self.read_csv(StringIO(data), usecols=usecols)
         expected = DataFrame({'a': [1,5], 'b': [2,6], 'c': [3,7], 'd': [4,8]})
         tm.assert_frame_equal(df, expected)
 
-        msg = 'Usecols do not match names'  ## from parsers.py CParserWrapper()
-        msg2 = 'is not in list' ## from parser.py _handle_usecols()
         usecols = ['a','b','c','f']
         with tm.assert_raises_regex(ValueError, re.compile("'" + msg + '||' + msg2 + "'")):
             self.read_csv(StringIO(data), usecols=usecols)
+
         usecols = ['a','b','f']
         with tm.assert_raises_regex(ValueError, re.compile("'" + msg + '||' + msg2 + "'")):
             self.read_csv(StringIO(data), usecols=usecols)
+
+        names = ['A', 'B', 'C', 'D']
+
+        df = self.read_csv(StringIO(data), header=0, names=names)
+        expected = DataFrame({'A': [1,5], 'B': [2,6], 'C': [3,7], 'D': [4,8]})
+        tm.assert_frame_equal(df, expected)
+
+        # usecols = ['A','C']
+        # df = self.read_csv(StringIO(data), header=0, names=names, usecols=usecols)
+        # expected = DataFrame({'A': [1,5], 'C': [3,7]})
+        # tm.assert_frame_equal(df, expected)
+        #
+        # usecols = [0,2]
+        # df = self.read_csv(StringIO(data), header=0, names=names, usecols=usecols)
+        # expected = DataFrame({'A': [1,5], 'C': [3,7]})
+        # tm.assert_frame_equal(df, expected)
+
+
+        usecols = ['A','B','C','f']
+        with tm.assert_raises_regex(ValueError, re.compile("'" + msg + '||' + msg2 + "'")):
+            self.read_csv(StringIO(data), header=0, names=names, usecols=usecols)
+        usecols = ['A','B','f']
+        with tm.assert_raises_regex(ValueError, re.compile("'" + msg + '||' + msg2 + "'")):
+            self.read_csv(StringIO(data), names=names, usecols=usecols)