hdr: add Section.different_first_page_hea.. setter

Author: scanny

docx/oxml/section.py

@@ -319,6 +319,13 @@ def titlePg_val(self):
             return False
         return titlePg.val
 
+    @titlePg_val.setter
+    def titlePg_val(self, value):
+        if value in [None, False]:
+            self._remove_titlePg()
+        else:
+            self.get_or_add_titlePg().val = value
+
     @property
     def top_margin(self):
         """

docx/section.py

@@ -70,6 +70,10 @@ def different_first_page_header_footer(self):
         """
         return self._sectPr.titlePg_val
 
+    @different_first_page_header_footer.setter
+    def different_first_page_header_footer(self, value):
+        self._sectPr.titlePg_val = value
+
     @lazyproperty
     def footer(self):
         """|_Footer| object representing default page footer for this section.

features/sct-section.feature

@@ -14,7 +14,6 @@ Feature: Access and change section properties
       | without         | False |
 
 
-  @wip
   Scenario Outline: Section.different_first_page_header_footer setter
     Given a Section object <with-or-without> a distinct first-page header as section
      When I assign <value> to section.different_first_page_header_footer

tests/test_section.py

@@ -102,6 +102,16 @@ def it_knows_when_it_displays_a_distinct_first_page_header(
 
         assert different_first_page_header_footer is expected_value
 
+    def it_can_change_whether_the_document_has_distinct_odd_and_even_headers(
+        self, diff_first_header_set_fixture
+    ):
+        sectPr, value, expected_xml = diff_first_header_set_fixture
+        section = Section(sectPr, None)
+
+        section.different_first_page_header_footer = value
+
+        assert sectPr.xml == expected_xml
+
     def it_provides_access_to_its_default_footer(
         self, document_part_, _Footer_, footer_
     ):
@@ -222,6 +232,20 @@ def diff_first_header_get_fixture(self, request):
         sectPr = element(sectPr_cxml)
         return sectPr, expected_value
 
+    @pytest.fixture(
+        params=[
+            ("w:sectPr", True, "w:sectPr/w:titlePg"),
+            ("w:sectPr/w:titlePg", False, "w:sectPr"),
+            ("w:sectPr/w:titlePg{w:val=1}", True, "w:sectPr/w:titlePg"),
+            ("w:sectPr/w:titlePg{w:val=off}", False, "w:sectPr"),
+        ]
+    )
+    def diff_first_header_set_fixture(self, request):
+        sectPr_cxml, value, expected_cxml = request.param
+        sectPr = element(sectPr_cxml)
+        expected_xml = xml(expected_cxml)
+        return sectPr, value, expected_xml
+
     @pytest.fixture(params=[
         ('w:sectPr/w:pgMar{w:left=120}',   'left_margin',      76200),
         ('w:sectPr/w:pgMar{w:right=240}',  'right_margin',    152400),