style: add Styles._get_by_id()

Steve Canny · Steve Canny · commit 7eb8d66e1372 · 2015-02-08T00:01:14.000-08:00
diff --git a/docx/styles/styles.py b/docx/styles/styles.py
@@ -61,7 +61,10 @@ def _get_by_id(self, style_id, style_type):
         default for *style_type* if *style_id* is not found or if the style
         having *style_id* is not of *style_type*.
         """
-        raise NotImplementedError
+        style = self._element.get_by_id(style_id)
+        if style is None or style.type != style_type:
+            return self.default(style_type)
+        return StyleFactory(style)
 
     @staticmethod
     def _translate_special_case_names(name):
diff --git a/tests/styles/test_styles.py b/tests/styles/test_styles.py
@@ -10,6 +10,7 @@
 
 import pytest
 
+from docx.enum.style import WD_STYLE_TYPE
 from docx.styles.style import BaseStyle
 from docx.styles.styles import Styles
 
@@ -52,11 +53,23 @@ def it_raises_on_style_not_found(self, get_raises_fixture):
     def it_can_get_a_style_of_type_by_id(self, get_by_id_fixture):
         styles, style_id, style_type = get_by_id_fixture[:3]
         default_calls, _get_by_id_calls, style_ = get_by_id_fixture[3:]
+
         style = styles.get_by_id(style_id, style_type)
+
         assert styles.default.call_args_list == default_calls
         assert styles._get_by_id.call_args_list == _get_by_id_calls
         assert style is style_
 
+    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:]
+
+        style = styles._get_by_id(style_id, style_type)
+
+        assert styles.default.call_args_list == default_calls
+        assert StyleFactory_.call_args_list == StyleFactory_calls
+        assert style is style_
+
     # fixture --------------------------------------------------------
 
     @pytest.fixture(params=[None, 'Foo'])
@@ -73,6 +86,27 @@ def get_by_id_fixture(self, request, default_, _get_by_id_, style_):
             style_
         )
 
+    @pytest.fixture(params=[
+        ('w:styles/w:style{w:type=paragraph,w:styleId=Foo}', 'Foo',
+         WD_STYLE_TYPE.PARAGRAPH),
+        ('w:styles/w:style{w:type=paragraph,w:styleId=Foo}', 'Bar',
+         WD_STYLE_TYPE.PARAGRAPH),
+        ('w:styles/w:style{w:type=table,w:styleId=Bar}',     'Bar',
+         WD_STYLE_TYPE.PARAGRAPH),
+    ])
+    def _get_by_id_fixture(self, request, default_, StyleFactory_, style_):
+        styles_cxml, style_id, style_type = request.param
+        styles_elm = element(styles_cxml)
+        style_elm = styles_elm[0]
+        styles = Styles(styles_elm)
+        default_calls = [] if style_id == 'Foo' else [call(style_type)]
+        StyleFactory_calls = [call(style_elm)] if style_id == 'Foo' else []
+        default_.return_value = StyleFactory_.return_value = style_
+        return (
+            styles, style_id, style_type, default_calls, StyleFactory_,
+            StyleFactory_calls, style_
+        )
+
     @pytest.fixture(params=[
         ('w:styles/(w:style{%s,w:styleId=Foobar},w:style,w:style)', 0),
         ('w:styles/(w:style,w:style{%s,w:styleId=Foobar},w:style)', 1),
