def METHOD_NAME(self, with_langevin=False):
    """Test velocity distribution of a dpd fluid with a single type."""
    N = 500
    system = self.system
    partcls = system.part.add(pos=system.box_l * np.random.random((N, 3)))
    kT = 2.3
    gamma = 1.5
    if with_langevin:
        system.thermostat.set_langevin(kT=kT, gamma=gamma, seed=41)
    system.thermostat.set_dpd(kT=kT, seed=42)
    system.non_bonded_inter[0, 0].dpd.set_params(
        weight_function=0, gamma=gamma, r_cut=1.5,
        trans_weight_function=0, trans_gamma=gamma, trans_r_cut=1.5)
    system.integrator.run(100)
    loops = 100
    v_stored = np.zeros((loops, N, 3))
    for i in range(loops):
        system.integrator.run(10)
        v_stored[i] = partcls.v
    v_minmax = 5
    bins = 5
    error_tol = 0.01
    self.check_velocity_distribution(
        v_stored.reshape((-1, 3)), v_minmax, bins, error_tol, kT)
    if not with_langevin:
        self.check_total_zero()