@Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result
                + ((variables == null) ? 0 : variables.hashCode());
        return result;
    }
@Test
    public void testHashCode() {
        UnmodifiableJMeterVariables otherUnmodifiables = new UnmodifiableJMeterVariables(vars);
        assertThat(unmodifiables.hashCode(), CoreMatchers.is(otherUnmodifiables.hashCode()));
    }