def METHOD_NAME(create_files_in_directory):
    filelist, outdir = create_files_in_directory
    fit = freesurfer.FitMSParams()
    # make sure command gets called
    assert fit.cmd == "mri_ms_fitparms"
    # test raising error with mandatory args absent
    with pytest.raises(ValueError):
        fit.run()
    # .inputs based parameters setting
    fit.inputs.in_files = filelist
    fit.inputs.out_dir = outdir
    assert fit.cmdline == "mri_ms_fitparms  {} {} {}".format(
        filelist[0],
        filelist[1],
        outdir,
    )
    # constructor based parameter setting
    fit2 = freesurfer.FitMSParams(
        in_files=filelist, te_list=[1.5, 3.5], flip_list=[20, 30], out_dir=outdir
    )
    assert fit2.cmdline == (
        "mri_ms_fitparms  -te %.3f -fa %.1f %s -te %.3f -fa %.1f %s %s"
        % (1.500, 20.0, filelist[0], 3.500, 30.0, filelist[1], outdir)
    )