e = new Entity(kindForClass(parentClass));
e.setProperty("aString", "z9");
ds.put(e);
beginTxn();
Parent parent = ((List<Parent>) pm.newQuery(
"select from " + parentClass.getName() + " where aString == 'z8'").execute()).get(0);
assertEquals(parentClass, parent.getClass());
assertEquals("z8", parent.getAString());
commitTxn();
beginTxn();
List<Parent> parents = ((List<Parent>) pm.newQuery(
"select from " + parentClass.getName() + " where aString >= 'z8' order by aString desc").execute());