public void testOnce() {
Solver solver = new Solver("OnceTest");
IntVar x = VariableFactory.enumerated("x", 1, 2, solver);
IntVar[] v = {x};
VariableSelector varsel = new InputOrder<>();
IntValueSelector valsel = new IntDomainMin();
DecisionOperator assgnt = DecisionOperator.int_eq;
solver.set(new Once(v, varsel, valsel, assgnt));
solver.findSolution();
Assert.assertTrue(x.getValue() == 1);
}