style: add DocumentPart._styles_part

Steve Canny · Steve Canny · commit adf878eafbc9 · 2014-12-27T22:51:55.000-08:00
* resequence Part.package property
diff --git a/docx/opc/part.py b/docx/opc/part.py
@@ -89,6 +89,13 @@ def load_rel(self, reltype, target, rId, is_external=False):
         """
         return self.rels.add_relationship(reltype, target, rId, is_external)
 
+    @property
+    def package(self):
+        """
+        |OpcPackage| instance this part belongs to.
+        """
+        return self._package
+
     @property
     def partname(self):
         """
@@ -104,13 +111,6 @@ def partname(self, partname):
             raise TypeError(tmpl % type(partname).__name__)
         self._partname = partname
 
-    @property
-    def package(self):
-        """
-        |OpcPackage| instance this part belongs to.
-        """
-        return self._package
-
     def part_related_by(self, reltype):
         """
         Return part to which this part has a relationship of *reltype*.
diff --git a/docx/parts/document.py b/docx/parts/document.py
@@ -17,6 +17,7 @@
 from ..section import Section
 from ..shape import InlineShape
 from ..shared import lazyproperty, Parented
+from .styles import StylesPart
 
 
 class DocumentPart(XmlPart):
@@ -125,7 +126,12 @@ def _styles_part(self):
         Instance of |StylesPart| for this document. Creates an empty styles
         part if one is not present.
         """
-        raise NotImplementedError
+        try:
+            return self.part_related_by(RT.STYLES)
+        except KeyError:
+            styles_part = StylesPart.default(self.package)
+            self.relate_to(styles_part, RT.STYLES)
+            return styles_part
 
 
 class _Body(BlockItemContainer):
diff --git a/docx/parts/styles.py b/docx/parts/styles.py
@@ -17,6 +17,14 @@ class StylesPart(XmlPart):
     Proxy for the styles.xml part containing style definitions for a document
     or glossary.
     """
+    @classmethod
+    def default(cls, package):
+        """
+        Return a newly created styles part, containing a default set of
+        elements.
+        """
+        raise NotImplementedError
+
     @classmethod
     def new(cls):
         """
diff --git a/tests/parts/test_document.py b/tests/parts/test_document.py
@@ -105,6 +105,23 @@ def it_knows_the_next_available_xml_id(self, next_id_fixture):
         document, expected_id = next_id_fixture
         assert document.next_id == expected_id
 
+    def it_provides_access_to_its_styles_part_to_help(
+            self, styles_part_get_fixture):
+        document_part, styles_part_ = styles_part_get_fixture
+        styles_part = document_part._styles_part
+        document_part.part_related_by.assert_called_once_with(RT.STYLES)
+        assert styles_part is styles_part_
+
+    def it_creates_default_styles_part_if_not_present_to_help(
+            self, styles_part_create_fixture):
+        document_part, StylesPart_, styles_part_ = styles_part_create_fixture
+        styles_part = document_part._styles_part
+        StylesPart_.default.assert_called_once_with(document_part.package)
+        document_part.relate_to.assert_called_once_with(
+            styles_part_, RT.STYLES
+        )
+        assert styles_part is styles_part_
+
     # fixtures -------------------------------------------------------
 
     @pytest.fixture
@@ -181,6 +198,21 @@ def styles_fixture(self, _styles_part_prop_, styles_part_, styles_):
         styles_part_.styles = styles_
         return document_part, styles_
 
+    @pytest.fixture
+    def styles_part_create_fixture(
+            self, package_, part_related_by_, StylesPart_, styles_part_,
+            relate_to_):
+        document_part = DocumentPart(None, None, None, package_)
+        part_related_by_.side_effect = KeyError
+        StylesPart_.default.return_value = styles_part_
+        return document_part, StylesPart_, styles_part_
+
+    @pytest.fixture
+    def styles_part_get_fixture(self, part_related_by_, styles_part_):
+        document_part = DocumentPart(None, None, None, None)
+        part_related_by_.return_value = styles_part_
+        return document_part, styles_part_
+
     @pytest.fixture
     def tables_fixture(self, document_part_body_, body_, tables_):
         document_part = DocumentPart(None, None, None, None)
@@ -257,6 +289,10 @@ def package_(self, request):
     def paragraphs_(self, request):
         return instance_mock(request, list)
 
+    @pytest.fixture
+    def part_related_by_(self, request):
+        return method_mock(request, DocumentPart, 'part_related_by')
+
     @pytest.fixture
     def relate_to_(self, request, rId_):
         relate_to_ = method_mock(request, DocumentPart, 'relate_to')
@@ -293,6 +329,10 @@ def start_type_(self, request):
     def styles_(self, request):
         return instance_mock(request, Styles)
 
+    @pytest.fixture
+    def StylesPart_(self, request):
+        return class_mock(request, 'docx.parts.document.StylesPart')
+
     @pytest.fixture
     def styles_part_(self, request):
         return instance_mock(request, StylesPart)
