final DefaultContext parent = new DefaultContext();
parent.put( "test", "ok test" );
parent.makeReadOnly();
final DefaultContext child = new DefaultContext( parent );
child.put( "check", new ResolvableString("This is an ${test}.") );
child.makeReadOnly();
final Context context = (Context) child;
assertTrue ( "ok test".equals( context.get( "test" ) ) );
assertTrue ( ! "This is an ${test}.".equals( context.get( "check" ) ) );
assertTrue ( "This is an ok test.".equals( context.get( "check" ) ) );