public void doTestBuiltins(Node nLow, Node nHigh) {
assertTrue( call(new Equal(), nLow, nLow) );
assertFalse( call(new Equal(), nLow, nHigh) );
assertFalse( call(new NotEqual(), nLow, nLow) );
assertTrue( call(new NotEqual(), nLow, nHigh) );
assertTrue( call(new LE(), nLow, nHigh) );
assertFalse( call(new LE(), nHigh, nLow) );
assertTrue( call(new LE(), nLow, nLow) );