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Background

In a work performed in collaboration with CTA, we prepared a small prototype to mock-up the ContainerServices class in C++. This mock-up allowed to retrieve components and make them interact, without requiring a CORBA connection and making it possible to do simple integration testings without ACS running and taking advantage of unit testing.

The benefits of this comes from performance and simplicity of the testing environment.

Limitations

There are several limitations, some of which could be mitigated by extending the ContainerServices mock-up functionalities. At the moment of writing:

  • Only retrieving components is implemented in the prototype (Alarms, CDB, etc. are missing)
  • This only works with components interacting in the same programming language

Prototype

The C++ prototype extends the ContainerServices class. The important methods to consider here, are the activateComponent/deactivateComponent which are to be used by the setUp and cleanUp methods in Unit testing.

Code Block
class MockContainerServices : public maci::ContainerServices {
  public:
    MockContainerServices(ACE_CString& componentName, PortableServer::POA_ptr poa);
    ~MockContainerServices();
    virtual CORBA::Object* getCORBAComponent(const char* name);
//...
    template<class TAdvancedObject> void activateComponent(const char* name) {
        TAdvancedObject* obj = new TAdvancedObject(name, this);
        obj->initialize();
        obj->execute();
        this->comps[name] = obj
    };
    virtual deactivateComponent(const char* name) {
        acscomponent::ACSComponentImpl* obj = dynamic_cast<acscomponent::ACSComponentImpl*>(this->comps[name]);
        try {
            obj->cleanUp();
        } catch (...) {
            obj->aboutToAbort();
        }
        this->comps.erase(name);
    }
  protected:
    std::map<std::string, CORBA::Object_var> comps;
};

The getCORBAComponent method was also extended in order to return the component from 'comps' the std::map:

Code Block
CORBA::Object* MockContainerServices::getCORBAComponent(const char* name){
    if (comps.find(name) == comps.end()) {
        maciErrType::CannotGetComponentExImpl ex(__FILE__, __LINE__, "MockContainerServices::getComponent");
        ex.setCURL(name);
        throw ex;
    }
    return CORBA::Object::_duplicate(comps[name].in());
}

Later on, in the test implementation we would do something similar to:

Code Block
MockContainerServices* mcs = nullptr;

setUp() {
    mcs = new MockContainerServices(cn, nullptr);
    mcs->activateComponent<MaciTestComponentImpl>("TEST_COMP1");
    mcs->activateComponent<MaciTestComponentImpl>("TEST_COMP2");
}

cleanUp() {
    mcs.deactivateComponent("TEST_COMP1");
    mcs.deactivateComponent("TEST_COMP2");
    delete mcs;
    mcs = nullptr;
}

//The tests should not know anything about the changes we've done, but they rely on this mcs instance just for convenience
test_example() {
    MACI_TEST::MaciTestComponent_var comp = mcs->getComponent<MACI_TEST::MaciTestComponent>("TEST_COMP1");
    comp->some_method(...); //If some_method retrieves a component, it should also work normally, since on creation, we passed an instance of MockContainerServices
}

Assume MaciTestComponent is an interface definition in an IDL file extending from ACS Component interface and that MaciTestComponentImpl is the actual implementation in C++.