@Test
public void clean()
{

    MatchBind m = new MatchBind();
    IntStream.range( 0, 10 ).forEach(
            n -> {
                m.setValue( Pattern.variable( "variable" + n ), Pattern.variable( "variable" + n ) );
                assertEquals( n + 1, m.size() );
            }
    );
    m.clean(5);
    assertEquals(5, m.size());
}