The answer is yes, you can be served on the 25th for a hearing on the 26th... but you would also have the right to ask for a continuance due to insufficient time to prepare.  In Texas, a 10 day notice is presumptively reasonable for some hearings.  Others, three days is reasonable.  For a final hearing, 45 days notice is required in civil courts.  If you were served with notice, you really do need to request a continuance and object to the hearing going forward due to the insufficient notice.  Also throw in that it's a violation of your due process rights to fail to give you sufficient time to prepare.