@Test
public void testIsTop() {

	SymbolicAddressMap m1 = map1();
	SymbolicAddressMap m2 = map2();
	assert(! m1.isTop());
	assert(! m2.isTop());
	assert(SymbolicAddressMap.top().isTop());
	m1.join(SymbolicAddressMap.top());
	assert(m1.isTop());
}