'Checks that the default value of None (for due) does not get marked as inherited when a
library is the root block.'

def test_library_metadata_no_inheritance(self):

    system = self.get_system()
    url_name = 'test1'
    start_xml = '\n                                <library    org="TestOrg"    library="TestLib"    display_name="stuff">\n                                                <course    org="{org}"    course="{course}"\n                                                                                url_name="{url_name}"    unicorn="purple">\n                                                                <chapter    url="hi"    url_name="ch"    display_name="CH">\n                                                                                <html    url_name="h"    display_name="H">Two    houses,    ...</html>\n                                                                </chapter>\n                                                </course>\n                                </library>'.format(org=ORG, course=COURSE, url_name=url_name)
    descriptor = system.process_xml(start_xml)
    LibraryXMLModuleStore.patch_descriptor_kvs(descriptor)
    compute_inherited_metadata(descriptor)
    descriptor = descriptor.get_children()[0]
    self.course_descriptor_no_inheritance_check(descriptor)
