sld: add Slide.follow_master_background getter

features/sld-slide.feature

@@ -14,7 +14,6 @@ Feature: slide properties
       | an overridden         |
 
 
-  @wip
   Scenario Outline: Slide.follow_master_background
     Given a Slide object having <default-or-overridden> background as slide
      Then slide.follow_master_background is <value>

pptx/oxml/slide.py

@@ -153,11 +153,14 @@ class CT_Slide(_BaseSlideElement):
 
     @classmethod
     def new(cls):
-        """
-        Return a new ``<p:sld>`` element configured as a base slide shape.
-        """
+        """Return new `p:sld` element configured as base slide shape."""
         return parse_xml(cls._sld_xml())
 
+    @property
+    def bg(self):
+        """Return `p:bg` grandchild or None if not present."""
+        return self.cSld.bg
+
     def get_or_add_childTnLst(self):
         """Return parent element for a new `p:video` child element.
 

pptx/slide.py

@@ -179,6 +179,20 @@ def background(self):
         """
         return super(Slide, self).background
 
+    @property
+    def follow_master_background(self):
+        """|True| if this slide inherits the slide master background.
+
+        Assigning |False| causes background inheritance from the master to be
+        interrupted; if there is no custom background for this slide,
+        a default background is added. If a custom background already exists
+        for this slide, assigning |False| has no effect.
+
+        Assigning |True| causes any custom background for this slide to be
+        deleted and inheritance from the master restored.
+        """
+        return self._element.bg is None
+
     @property
     def has_notes_slide(self):
         """

tests/test_slide.py

@@ -327,6 +327,11 @@ def it_provides_access_to_its_background(self, background_fixture):
         _BaseSlide_background_.assert_called_once_with()
         assert background is background_
 
+    def it_knows_whether_it_follows_the_mstr_bkgd(self, follow_get_fixture):
+        slide, expected_value = follow_get_fixture
+        follows = slide.follow_master_background
+        assert follows is expected_value
+
     def it_knows_whether_it_has_a_notes_slide(self, has_notes_slide_fixture):
         slide, expected_value = has_notes_slide_fixture
         assert slide.has_notes_slide is expected_value
@@ -365,6 +370,15 @@ def background_fixture(self, _BaseSlide_background_, background_):
         _BaseSlide_background_.return_value = background_
         return slide, _BaseSlide_background_, background_
 
+    @pytest.fixture(params=[
+        ('p:sld/p:cSld',      True),
+        ('p:sld/p:cSld/p:bg', False),
+    ])
+    def follow_get_fixture(self, request):
+        pSld_cxml, expected_value = request.param
+        slide = Slide(element(pSld_cxml), None)
+        return slide, expected_value
+
     @pytest.fixture
     def has_notes_slide_fixture(self, part_prop_, slide_part_):
         slide = Slide(None, None)