FromTest.java

@Test
    public void testEnum() {
        final String drl =
                "package org.drools.compiler.integrationtests.operators;" +
                "import " + Person.class.getCanonicalName() + ";\n" +
                "import " + Pet.class.getCanonicalName() + ";\n" +
                "rule \"Enum rule\" \n" +
                "when \n" +
                "    $p : Person () \n" +
                "    $pet : Pet (type == Pet.PetType.DOG) from $p.getPets().values() \n" +
                "then \n" +
                "end";

        final KieBase kbase = KieBaseUtil.getKieBaseFromKieModuleFromDrl("from-test",
                                                                         kieBaseTestConfiguration,
                                                                         drl);
        final KieSession ksession = kbase.newKieSession();
        try {
            final Person person = new Person("dog lady");
            final Pet pet1 = new Pet(Pet.PetType.DOG, 3);
            final Pet pet2 = new Pet(Pet.PetType.DOG, 5);
            person.addPet("dog1", pet1);
            person.addPet("dog2", pet2);

            ksession.insert(person);
            assertEquals(2, ksession.fireAllRules());
        } finally {
            ksession.dispose();
        }
    }