def METHOD_NAME(self):
    # creating a Shell object with no argument will result in bash shell
    shell = Shell()
    # checking if shell.name is bash
    assert shell.name == "bash"
    # check shell.path and shebang is full path to bash reported by shutil.which
    assert shell.path == shutil.which("bash")
    assert shell.shebang == f"#!{shutil.which('bash')}"