style: add Styles.get_style_id()

Steve Canny · Steve Canny · commit 180de12ae968 · 2015-02-08T00:01:15.000-08:00
diff --git a/docx/styles/styles.py b/docx/styles/styles.py
@@ -9,7 +9,7 @@
 )
 
 from ..shared import ElementProxy
-from .style import StyleFactory
+from .style import BaseStyle, StyleFactory
 
 
 class Styles(ElementProxy):
@@ -67,7 +67,12 @@ def get_style_id(self, style_or_name, style_type):
         defined. Raises |ValueError| if the target style is not of
         *style_type*.
         """
-        raise NotImplementedError
+        if style_or_name is None:
+            return None
+        elif isinstance(style_or_name, BaseStyle):
+            return self._get_style_id_from_style(style_or_name, style_type)
+        else:
+            return self._get_style_id_from_name(style_or_name, style_type)
 
     def _get_by_id(self, style_id, style_type):
         """
@@ -80,6 +85,22 @@ def _get_by_id(self, style_id, style_type):
             return self.default(style_type)
         return StyleFactory(style)
 
+    def _get_style_id_from_name(self, style_name, style_type):
+        """
+        Return the id of the style of *style_type* corresponding to
+        *style_name*. Returns |None| if that style is the default style for
+        *style_type*. Raises |ValueError| if the named style is not found in
+        the document or does not match *style_type*.
+        """
+        raise NotImplementedError
+
+    def _get_style_id_from_style(self, style, style_type):
+        """
+        Return the id of *style*, or |None| if it is the default style of
+        *style_type*. Raises |ValueError| if style is not of *style_type*.
+        """
+        raise NotImplementedError
+
     @staticmethod
     def _translate_special_case_names(name):
         """
diff --git a/tests/styles/test_styles.py b/tests/styles/test_styles.py
@@ -69,6 +69,16 @@ def it_can_get_a_style_of_type_by_id(self, get_by_id_fixture):
         assert styles._get_by_id.call_args_list == _get_by_id_calls
         assert style is style_
 
+    def it_can_get_a_style_id(self, get_style_id_fixture):
+        styles, style_or_name, style_type = get_style_id_fixture[:3]
+        style_calls, name_calls, style_id_ = get_style_id_fixture[3:]
+
+        style_id = styles.get_style_id(style_or_name, style_type)
+
+        assert styles._get_style_id_from_style.call_args_list == style_calls
+        assert styles._get_style_id_from_name.call_args_list == name_calls
+        assert style_id is style_id_
+
     def it_gets_a_style_by_id_to_help(self, _get_by_id_fixture):
         styles, style_id, style_type, default_calls = _get_by_id_fixture[:4]
         StyleFactory_, StyleFactory_calls, style_ = _get_by_id_fixture[4:]
@@ -116,6 +126,27 @@ def get_by_id_fixture(self, request, default_, _get_by_id_, style_):
             style_
         )
 
+    @pytest.fixture(params=[None, BaseStyle(None), 'Style Name'])
+    def get_style_id_fixture(self, request, _get_style_id_from_style_,
+                             _get_style_id_from_name_):
+        style_or_name, style_type = request.param, 1
+        styles = Styles(None)
+        style_calls = (
+            [call(style_or_name, style_type)]
+            if isinstance(style_or_name, BaseStyle) else []
+        )
+        name_calls = (
+            [call(style_or_name, style_type)]
+            if style_or_name == 'Style Name' else []
+        )
+        style_id_ = None if style_or_name is None else 'StyleName'
+        _get_style_id_from_style_.return_value = style_id_
+        _get_style_id_from_name_.return_value = style_id_
+        return (
+            styles, style_or_name, style_type, style_calls, name_calls,
+            style_id_
+        )
+
     @pytest.fixture(params=[
         ('w:styles/w:style{w:type=paragraph,w:styleId=Foo}', 'Foo',
          WD_STYLE_TYPE.PARAGRAPH),
@@ -205,6 +236,14 @@ def default_(self, request):
     def _get_by_id_(self, request):
         return method_mock(request, Styles, '_get_by_id')
 
+    @pytest.fixture
+    def _get_style_id_from_name_(self, request):
+        return method_mock(request, Styles, '_get_style_id_from_name')
+
+    @pytest.fixture
+    def _get_style_id_from_style_(self, request):
+        return method_mock(request, Styles, '_get_style_id_from_style')
+
     @pytest.fixture
     def style_(self, request):
         return instance_mock(request, BaseStyle)
