Torque3D/Engine/source/component/test/simpleComponentTest.cpp

//-----------------------------------------------------------------------------
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#ifdef TORQUE_TESTS_ENABLED
#include "testing/unitTesting.h"
#include "component/simpleComponent.h"

TEST(SimpleComponent, SimpleComponent)
{
   // When instantiating, and working with a SimObject in C++ code, such as
   // a unit test, you *may not* allocate a SimObject off of the stack. 
   //
   // For example:
   //    SimpleComponent sc; 
   // is a stack allocation. This memory is allocated off of the program stack
   // when the function is called. SimObject deletion is done via SimObject::deleteObject()
   // and the last command of this method is 'delete this;' That command will
   // cause an assert if it is called on stack-allocated memory. Therefor, when
   // instantiating SimObjects in C++ code, it is imperitive that you keep in
   // mind that if any script calls 'delete()' on that SimObject, or any other
   // C++ code calls 'deleteObject()' on that SimObject, it will crash.
   SimpleComponent *sc = new SimpleComponent();

   // SimObject::registerObject must be called on a SimObject before it is
   // fully 'hooked in' to the engine. 
   //
   // Tracing execution of this function will let you see onAdd get called on
   // the component, and you will see it cache the interface we exposed.
   sc->registerObject();

   // It is *not* required that a component always be owned by a component (obviously)
   // however I am using an owner so that you can trace execution of recursive
   // calls to cache interfaces and such.
   SimComponent *testOwner = new SimComponent();

   // Add the test component to it's owner. This will set the 'mOwner' field
   // of 'sc' to the address of 'testOwner'
   testOwner->addComponent( sc );

   // If you step-into this registerObject the same way as the previous one, 
   // you will be able to see the recursive caching of the exposed interface.
   testOwner->registerObject();

   // Now to prove that object composition is working properly, lets ask 
   // both of these components for their interface lists...

   // The ComponentInterfaceList is a typedef for type 'VectorPtr<ComponentInterface *>'
   // and it will be used by getInterfaces() to store the results of the interface
   // query. This is the "complete" way to obtain an interface, and it is too
   // heavy-weight for most cases. A simplified query will be performed next, 
   // to demonstrate the usage of both.
   ComponentInterfaceList iLst;

   // This query requests all interfaces, on all components, regardless of name
   // or owner.
   sc->getInterfaces( &iLst, 
      // This is the type field. I am passing NULL here to signify that the query
      // should match all values of 'type' in the list.
      NULL,

      // The name field, let's pass NULL again just so when you trace execution
      // you can see how queries work in the simple case, first.
      NULL );

   // Lets process the list that we've gotten back, and find the interface that
   // we want.
   SimpleComponentInterface *scQueriedInterface = NULL;

   for( ComponentInterfaceListIterator i = iLst.begin(); i != iLst.end(); i++ )
   {
      scQueriedInterface = dynamic_cast<SimpleComponentInterface *>( *i );

      if( scQueriedInterface != NULL )
         break;
   }

   AssertFatal( scQueriedInterface != NULL, "No valid SimpleComponentInterface was found in query" );

   // Lets do it again, only we will execute the query on the parent instead,
   // in a simplified way. Remember the parent component doesn't expose any 
   // interfaces at all, so the success of this behavior is entirely dependent 
   // on the recursive registration that occurs in registerInterfaces()
   SimpleComponentInterface *ownerQueriedInterface = testOwner->getInterface<SimpleComponentInterface>();

   AssertFatal( ownerQueriedInterface != NULL, "No valid SimpleComponentInterface was found in query" );

   // We should now have two pointers to the same interface obtained by querying
   // different components.
   EXPECT_EQ( ownerQueriedInterface, scQueriedInterface )
      << "This really shouldn't be possible to fail given the setup of the test";

   // Lets call the method that was exposed on the component via the interface.
   // Trace the execution of this function, if you wish.
   EXPECT_TRUE( ownerQueriedInterface->isFortyTwo( 42 ) )
      << "Don't panic, but it's a bad day in the component system.";
   EXPECT_TRUE( scQueriedInterface->isFortyTwo( 42 ) )
      << "Don't panic, but it's a bad day in the component system.";

   // So there you have it. Writing a simple component that exposes a cached
   // interface, and testing it. It's time to clean up.
   testOwner->removeComponent( sc );

   sc->deleteObject();
   testOwner->deleteObject();

   // Interfaces do not need to be freed. In Juggernaught, these will be ref-counted
   // for more robust behavior. Right now, however, the values of our two interface
   // pointers, scQueriedInterface and ownerQueriedInterface, reference invalid
   // memory. 
};

#endif