tbl: enable sliced access to _Rows

Steve Canny · Steve Canny · commit 378d206cd405 · 2014-12-14T23:30:36.000-08:00
diff --git a/docx/table.py b/docx/table.py
@@ -370,8 +370,8 @@ def _index(self):
 
 class _Rows(Parented):
     """
-    Sequence of |_Row| instances corresponding to the rows in a table.
-    Supports ``len()``, iteration and indexed access.
+    Sequence of |_Row| objects corresponding to the rows in a table.
+    Supports ``len()``, iteration, indexed access, and slicing.
     """
     def __init__(self, tbl, parent):
         super(_Rows, self).__init__(parent)
@@ -381,12 +381,7 @@ def __getitem__(self, idx):
         """
         Provide indexed access, (e.g. 'rows[0]')
         """
-        try:
-            tr = self._tbl.tr_lst[idx]
-        except IndexError:
-            msg = "row index [%d] out of range" % idx
-            raise IndexError(msg)
-        return _Row(tr, self)
+        return list(self)[idx]
 
     def __iter__(self):
         return (_Row(tr, self) for tr in self._tbl.tr_lst)
diff --git a/tests/test_table.py b/tests/test_table.py
@@ -678,6 +678,15 @@ def it_provides_indexed_access_to_rows(self, rows_fixture):
             row = rows[idx]
             assert isinstance(row, _Row)
 
+    def it_provides_sliced_access_to_rows(self, slice_fixture):
+        rows, start, end, expected_count = slice_fixture
+        slice_of_rows = rows[start:end]
+        assert len(slice_of_rows) == expected_count
+        tr_lst = rows._tbl.tr_lst
+        for idx, row in enumerate(slice_of_rows):
+            assert tr_lst.index(row._tr) == start + idx
+            assert isinstance(row, _Row)
+
     def it_raises_on_indexed_access_out_of_range(self, rows_fixture):
         rows, row_count = rows_fixture
         with pytest.raises(IndexError):
@@ -700,6 +709,16 @@ def rows_fixture(self):
         rows = _Rows(tbl, None)
         return rows, row_count
 
+    @pytest.fixture(params=[
+        (3, 1,  3, 2),
+        (3, 0, -1, 2),
+    ])
+    def slice_fixture(self, request):
+        row_count, start, end, expected_count = request.param
+        tbl = _tbl_bldr(rows=row_count, cols=2).element
+        rows = _Rows(tbl, None)
+        return rows, start, end, expected_count
+
     @pytest.fixture
     def table_fixture(self, table_):
         rows = _Rows(None, table_)
