Add addition test for pandas.csv_read to test variations of index_col kwarg.

Author: santegoeds

pandas/io/tests/test_parsers.py

@@ -2316,6 +2316,59 @@ def test_empty_with_reversed_multiindex(self):
                              index=MultiIndex.from_arrays([[]] * 2, names=['y', 'x']))
         tm.assert_frame_equal(result, expected)
 
+    def test_empty_index_col_scenarios(self):
+        data = 'x,y,z'
+
+        # None, no index
+        index_col, expected = None, DataFrame([], columns=list('xyz')),
+        tm.assert_frame_equal(self.read_csv(StringIO(data), index_col=index_col), expected)
+
+        # False, no index
+        index_col, expected = False, DataFrame([], columns=list('xyz')),
+        tm.assert_frame_equal(self.read_csv(StringIO(data), index_col=index_col), expected)
+
+        # int, first column
+        index_col, expected = 0, DataFrame([], columns=['y', 'z'], index=Index([], name='x'))
+        tm.assert_frame_equal(self.read_csv(StringIO(data), index_col=index_col), expected)
+
+        # int, not first column
+        index_col, expected = 1, DataFrame([], columns=['x', 'z'], index=Index([], name='y'))
+        tm.assert_frame_equal(self.read_csv(StringIO(data), index_col=index_col), expected)
+
+        # str, first column
+        index_col, expected = 'x', DataFrame([], columns=['y', 'z'], index=Index([], name='x'))
+        tm.assert_frame_equal(self.read_csv(StringIO(data), index_col=index_col), expected)
+
+        # str, not the first column
+        index_col, expected = 'y', DataFrame([], columns=['x', 'z'], index=Index([], name='y'))
+        tm.assert_frame_equal(self.read_csv(StringIO(data), index_col=index_col), expected)
+
+        # list of int
+        index_col, expected = [0, 1], DataFrame([], columns=['z'],
+                                                index=MultiIndex.from_arrays([[]] * 2, names=['x', 'y']))
+        tm.assert_frame_equal(self.read_csv(StringIO(data), index_col=index_col), expected)
+
+        # list of str
+        index_col, expected = (
+            ['x', 'y'],
+            DataFrame([], columns=['z'], index=MultiIndex.from_arrays([[]] * 2, names=['x', 'y']))
+        )
+        tm.assert_frame_equal(self.read_csv(StringIO(data), index_col=index_col), expected)
+
+        # list of int, reversed sequence
+        index_col, expected = (
+            [1, 0],
+            DataFrame([], columns=['z'], index=MultiIndex.from_arrays([[]] * 2, names=['y', 'x']))
+        )
+        tm.assert_frame_equal(self.read_csv(StringIO(data), index_col=index_col), expected)
+
+        # list of str, reversed sequence
+        index_col, expected = (
+            ['y', 'x'],
+            DataFrame([], columns=['z'], index=MultiIndex.from_arrays([[]] * 2, names=['y', 'x']))
+        )
+        tm.assert_frame_equal(self.read_csv(StringIO(data), index_col=index_col), expected)
+
     def test_empty_with_index_col_false(self):
         # GH 10413
         data = 'x,y'