def METHOD_NAME(self):
    directory_names = ["foo", 'bar', 'bat', 'bamus', 'batis', 'bant']
    accumulated = ""
    for index,i in enumerate(directory_names):
        accumulated += (i + '/')
        self.admin.assert_icommand(["imkdir", accumulated])
        self.admin.assert_icommand("itree", 'STDOUT_SINGLELINE', ["  " * index + i])
    for index,item in enumerate(directory_names):
        self.admin.assert_icommand(["itree", "-L", str(1 + index)], 'STDOUT_SINGLELINE', ["  " * (1 + index) + item])