style: add _ParaStyle.next_paragraph_style setter

Steve Canny · Steve Canny · commit 7e5471eb346c · 2015-02-08T00:01:49.000-08:00
diff --git a/docx/styles/style.py b/docx/styles/style.py
@@ -248,6 +248,13 @@ def next_paragraph_style(self):
             return self
         return StyleFactory(next_style_elm)
 
+    @next_paragraph_style.setter
+    def next_paragraph_style(self, style):
+        if style is None or style.style_id == self.style_id:
+            self._element._remove_next()
+        else:
+            self._element.get_or_add_next().val = style.style_id
+
     @property
     def paragraph_format(self):
         """
diff --git a/features/sty-style-props.feature b/features/sty-style-props.feature
@@ -92,7 +92,6 @@ Feature: Get and set style properties
       | Foobar     | Sub Normal |
 
 
-  @wip
   Scenario Outline: Set next paragraph style
     Given a style having next paragraph style set to <setting>
      When I assign <new-value> to style.next_paragraph_style
diff --git a/tests/styles/test_style.py b/tests/styles/test_style.py
@@ -468,6 +468,11 @@ def it_knows_its_next_paragraph_style(self, next_get_fixture):
         style, expected_value = next_get_fixture
         assert style.next_paragraph_style == expected_value
 
+    def it_can_change_its_next_paragraph_style(self, next_set_fixture):
+        style, next_style, expected_xml = next_set_fixture
+        style.next_paragraph_style = next_style
+        assert style.element.xml == expected_xml
+
     def it_provides_access_to_its_paragraph_format(self, parfmt_fixture):
         style, ParagraphFormat_, paragraph_format_ = parfmt_fixture
         paragraph_format = style.paragraph_format
@@ -502,6 +507,27 @@ def next_get_fixture(self, request):
             next_style = style
         return style, next_style
 
+    @pytest.fixture(params=[
+        ('H', 'B',  'w:style{w:type=paragraph,w:styleId=H}/w:next{w:val=B}'),
+        ('H', None, 'w:style{w:type=paragraph,w:styleId=H}'),
+        ('H', 'H',  'w:style{w:type=paragraph,w:styleId=H}'),
+    ])
+    def next_set_fixture(self, request):
+        style_name, next_style_name, style_cxml = request.param
+        styles = element(
+            'w:styles/('
+            'w:style{w:type=paragraph,w:styleId=H},'
+            'w:style{w:type=paragraph,w:styleId=B})'
+        )
+        style_elms = {'H': styles[0], 'B': styles[1]}
+        style = _ParagraphStyle(style_elms[style_name])
+        next_style = (
+            None if next_style_name is None else
+            _ParagraphStyle(style_elms[next_style_name])
+        )
+        expected_xml = xml(style_cxml)
+        return style, next_style, expected_xml
+
     @pytest.fixture
     def parfmt_fixture(self, ParagraphFormat_, paragraph_format_):
         style = _ParagraphStyle(element('w:style'))
