style: add _CharacterStyle.base_style setter

Steve Canny · Steve Canny · commit b595e4463b25 · 2015-02-08T00:01:40.000-08:00
diff --git a/docx/oxml/styles.py b/docx/oxml/styles.py
@@ -50,6 +50,23 @@ class CT_Style(BaseOxmlElement):
     customStyle = OptionalAttribute('w:customStyle', ST_OnOff)
     del _tag_seq
 
+    @property
+    def basedOn_val(self):
+        """
+        Value of `w:basedOn/@w:val` or |None| if not present.
+        """
+        basedOn = self.basedOn
+        if basedOn is None:
+            return None
+        return basedOn.val
+
+    @basedOn_val.setter
+    def basedOn_val(self, value):
+        if value is None:
+            self._remove_basedOn()
+        else:
+            self.get_or_add_basedOn().val = value
+
     @property
     def base_style(self):
         """
diff --git a/docx/styles/style.py b/docx/styles/style.py
@@ -129,6 +129,11 @@ def base_style(self):
             return None
         return StyleFactory(base_style)
 
+    @base_style.setter
+    def base_style(self, style):
+        style_id = style.style_id if style is not None else None
+        self._element.basedOn_val = style_id
+
 
 class _ParagraphStyle(_CharacterStyle):
     """
diff --git a/features/sty-style-props.feature b/features/sty-style-props.feature
@@ -14,7 +14,6 @@ Feature: Get and set style properties
       | Normal     | styles['Normal'] |
 
 
-  @wip
   Scenario Outline: Set base style
     Given a style based on <base-style>
      When I assign <assigned-value> to style.base_style
diff --git a/tests/styles/test_style.py b/tests/styles/test_style.py
@@ -211,6 +211,11 @@ def it_knows_which_style_it_is_based_on(self, base_get_fixture):
         assert StyleFactory_.call_args_list == StyleFactory_calls
         assert base_style == base_style_
 
+    def it_can_change_its_base_style(self, base_set_fixture):
+        style, value, expected_xml = base_set_fixture
+        style.base_style = value
+        assert style._element.xml == expected_xml
+
     # fixture --------------------------------------------------------
 
     @pytest.fixture(params=[
@@ -234,8 +239,28 @@ def base_get_fixture(self, request, StyleFactory_):
             expected_value = None
         return style, StyleFactory_, StyleFactory_calls, expected_value
 
+    @pytest.fixture(params=[
+        ('w:style',                       'Foo',
+         'w:style/w:basedOn{w:val=Foo}'),
+        ('w:style/w:basedOn{w:val=Foo}',  'Bar',
+         'w:style/w:basedOn{w:val=Bar}'),
+        ('w:style/w:basedOn{w:val=Bar}',  None,
+         'w:style'),
+    ])
+    def base_set_fixture(self, request, style_):
+        style_cxml, base_style_id, expected_style_cxml = request.param
+        style = _CharacterStyle(element(style_cxml))
+        style_.style_id = base_style_id
+        base_style = style_ if base_style_id is not None else None
+        expected_xml = xml(expected_style_cxml)
+        return style, base_style, expected_xml
+
     # fixture components ---------------------------------------------
 
+    @pytest.fixture
+    def style_(self, request):
+        return instance_mock(request, BaseStyle)
+
     @pytest.fixture
     def StyleFactory_(self, request):
         return function_mock(request, 'docx.styles.style.StyleFactory')
