style: add _CharacterStyle.base_style getter

Steve Canny · Steve Canny · commit b8abd2759bac · 2015-02-08T00:01:40.000-08:00
diff --git a/docx/oxml/__init__.py b/docx/oxml/__init__.py
@@ -114,9 +114,10 @@ def OxmlElement(nsptag_str, attrs=None, nsdecls=None):
 register_element_cls('wp:inline',     CT_Inline)
 
 from .styles import CT_Style, CT_Styles
-register_element_cls('w:name',   CT_String)
-register_element_cls('w:style',  CT_Style)
-register_element_cls('w:styles', CT_Styles)
+register_element_cls('w:basedOn', CT_String)
+register_element_cls('w:name',    CT_String)
+register_element_cls('w:style',   CT_Style)
+register_element_cls('w:styles',  CT_Styles)
 
 from .table import (
     CT_Row, CT_Tbl, CT_TblGrid, CT_TblGridCol, CT_TblLayoutType, CT_TblPr,
diff --git a/docx/oxml/styles.py b/docx/oxml/styles.py
@@ -42,13 +42,29 @@ class CT_Style(BaseOxmlElement):
         'w:tblPr', 'w:trPr', 'w:tcPr', 'w:tblStylePr'
     )
     name = ZeroOrOne('w:name', successors=_tag_seq[1:])
+    basedOn = ZeroOrOne('w:basedOn', successors=_tag_seq[3:])
     pPr = ZeroOrOne('w:pPr', successors=_tag_seq[17:])
     type = OptionalAttribute('w:type', WD_STYLE_TYPE)
     styleId = OptionalAttribute('w:styleId', ST_String)
     default = OptionalAttribute('w:default', ST_OnOff)
     customStyle = OptionalAttribute('w:customStyle', ST_OnOff)
     del _tag_seq
 
+    @property
+    def base_style(self):
+        """
+        Sibling CT_Style element this style is based on or |None| if no base
+        style or base style not found.
+        """
+        basedOn = self.basedOn
+        if basedOn is None:
+            return None
+        styles = self.getparent()
+        base_style = styles.get_by_id(basedOn.val)
+        if base_style is None:
+            return None
+        return base_style
+
     def delete(self):
         """
         Remove this `w:style` element from its parent `w:styles` element.
diff --git a/docx/styles/style.py b/docx/styles/style.py
@@ -118,6 +118,17 @@ class _CharacterStyle(BaseStyle):
 
     __slots__ = ()
 
+    @property
+    def base_style(self):
+        """
+        Style object this style inherits from or |None| if this style is
+        not based on another style.
+        """
+        base_style = self._element.base_style
+        if base_style is None:
+            return None
+        return StyleFactory(base_style)
+
 
 class _ParagraphStyle(_CharacterStyle):
     """
diff --git a/features/sty-style-props.feature b/features/sty-style-props.feature
@@ -4,7 +4,6 @@ Feature: Get and set style properties
   I need a set of read/write style properties
 
 
-  @wip
   Scenario Outline: Get base style
     Given a style based on <base-style>
      Then style.base_style is <value>
diff --git a/tests/styles/test_style.py b/tests/styles/test_style.py
@@ -17,7 +17,7 @@
 )
 
 from ..unitutil.cxml import element, xml
-from ..unitutil.mock import class_mock, instance_mock
+from ..unitutil.mock import call, class_mock, function_mock, instance_mock
 
 
 class DescribeStyleFactory(object):
@@ -198,3 +198,44 @@ def type_get_fixture(self, request):
         style_cxml, expected_value = request.param
         style = BaseStyle(element(style_cxml))
         return style, expected_value
+
+
+class Describe_CharacterStyle(object):
+
+    def it_knows_which_style_it_is_based_on(self, base_get_fixture):
+        style, StyleFactory_, StyleFactory_calls, base_style_ = (
+            base_get_fixture
+        )
+        base_style = style.base_style
+
+        assert StyleFactory_.call_args_list == StyleFactory_calls
+        assert base_style == base_style_
+
+    # fixture --------------------------------------------------------
+
+    @pytest.fixture(params=[
+        ('w:styles/(w:style{w:styleId=Foo},w:style/w:basedOn{w:val=Foo})',
+         1, 0),
+        ('w:styles/(w:style{w:styleId=Foo},w:style/w:basedOn{w:val=Bar})',
+         1, -1),
+        ('w:styles/w:style',
+         0, -1),
+    ])
+    def base_get_fixture(self, request, StyleFactory_):
+        styles_cxml, style_idx, base_style_idx = request.param
+        styles = element(styles_cxml)
+        style = _CharacterStyle(styles[style_idx])
+        if base_style_idx >= 0:
+            base_style = styles[base_style_idx]
+            StyleFactory_calls = [call(base_style)]
+            expected_value = StyleFactory_.return_value
+        else:
+            StyleFactory_calls = []
+            expected_value = None
+        return style, StyleFactory_, StyleFactory_calls, expected_value
+
+    # fixture components ---------------------------------------------
+
+    @pytest.fixture
+    def StyleFactory_(self, request):
+        return function_mock(request, 'docx.styles.style.StyleFactory')
