@Test
public void testNonLiteralDefaultValue() {

    System.out.println("   non-literal default value");
    int x = 21;
    Expression defaultExpr = ff.add(ff.literal(x), ff.literal(x));
    Object result = ff.function("env", ff.literal("doesnotexist"), defaultExpr).evaluate(null);
    int value = ((Number) result).intValue();
    assertEquals(x + x, value);
}