"x = y");
NType xtype = idx.lookupQnameType("test.x");
assertTrue(xtype instanceof NUnionType);
// Jump through some hoops to allow for either order in the union.
Set<NType> types = xtype.asUnionType().getTypes();
assertEquals(2, types.size());
NType[] array = types.toArray(new NType[2]);
boolean array0List = array[0] instanceof NListType;
boolean array1List = array[1] instanceof NListType;