instance.globalUpdate();
garden = instance.marginalize();
assertFalse(garden.isWetGrass() ); // still grass is not wet
ksession.delete( fh3 ); // no sprinkler support now
ksession.fireAllRules();
instance.globalUpdate();
garden = instance.marginalize();
assertTrue(garden.isWetGrass()); // grass is wet again
}