def METHOD_NAME(self):
    """
    The sum of relative post trusts must equal 1. Post-trusts must also
    assign at least `PRETRUST_BIAS` to pre-trusted users. Finally, it
    should assign a zero trust to non-pre-trusted non-vouched users.
    """
    pretrusts = self.get_random_pretrust_vector()
    vouch_matrix = self.get_random_vouch_matrix()
    weighted_vouch_matrix = get_weighted_vouch_matrix(vouch_matrix)
    byztrusts = compute_byztrust(weighted_vouch_matrix, pretrusts)
    # ensure that all pre-trusted users have a positive relative post-trust
    for byztrust, pretrust in zip(byztrusts, pretrusts):
        if pretrust > 0:
            self.assertGreaterEqual(byztrust, TRUSTED_EMAIL_PRETRUST)
    # ensure that untrusted users than aren't vouched for don't get trust
    untrusted_user = self._nb_users - 1
    pretrusts[untrusted_user] = 0
    vouch_matrix[:, untrusted_user] = 0
    weighted_vouch_matrix = get_weighted_vouch_matrix(vouch_matrix)
    byztrusts = compute_byztrust(weighted_vouch_matrix, pretrusts)
    self.assertAlmostEqual(byztrusts[untrusted_user], 0)