Fixes #583 - Allow inserting columns for dataset with headers and no …

…values

src/tablib/core.py

@@ -366,19 +366,14 @@ def _set_dict(self, pickle):
     dict = property(_get_dict, _set_dict)
 
     def _clean_col(self, col):
-        """Prepares the given column for insert/append."""
+        """Prepares the given column for insert/append. `col` is not supposed to
+           contain any header value.
+        """
 
         col = list(col)
 
-        if self.headers:
-            header = [col.pop(0)]
-        else:
-            header = []
-
         if len(col) == 1 and hasattr(col[0], '__call__'):
-
             col = list(map(col[0], self._data))
-        col = tuple(header + col)
 
         return col
 

tests/test_tablib.py

@@ -117,10 +117,19 @@ def test_add_column(self):
 
         # With Headers
         data.headers = ('fname', 'lname')
-        new_col = [21, 22]
-        data.append_col(new_col, header='age')
+        age_col = [21, 22]
+        data.append_col(age_col, header='age')
+        size_col = [1.65, 1.86]
+        data.insert_col(1, size_col, header='size')
 
-        self.assertEqual(data['age'], new_col)
+        self.assertEqual(data['age'], age_col)
+        self.assertEqual(data['size'], size_col)
+
+    def test_add_column_no_data_with_headers(self):
+        """Verify adding empty column when dataset has only headers."""
+        data.headers = ('fname', 'lname')
+        data.insert_col(1, [], header='size')
+        self.assertEqual(data.headers, ['fname', 'size', 'lname'])
 
     def test_add_column_no_data_no_headers(self):
         """Verify adding new column with no headers."""