Re: [Cppunit-devel] hierarchy sample bug...

[Baptiste L. <bl...@cl...>]

>     Humm, just one thing that popup in my mind: who owns the fixture given
> to the test caller ? That's may be the reason why it is done that way...
>
> I guess it had something to do with the automatic test registration thing,
> which has been removed anyway.
    No, it was done that way in Michael Feather version. And if I understood
thing well, it's also done that way in junit.

> Because I did not have a clear picture of all use cases of TestCaller, the
> current implementation allows the TestCaller to own the Fixture or not:
> If the Fixture is passed through a reference the TestCaller won't own it.
> If the Fixture is passed through a pointer the TestCaller will assume
> ownership and destroy it in its destructor.

    Things I want to point out:
    - in about 95% of the case, you use the default constructor for the
fixture.
    - Even when subclassing a test case, you override the setUp() and
tearOff() method, and would still have a default constructor.
    - non default constructor would most likely be used for a test case with
are parameterized (a generic test case that load tests from a file for
example). I don't see that happening often. And in all likelyhood, you would
more likely overide runTests() than create a suite using some test
callers...

    Well, here I presents the test cases of use of the TestCaller.

    The common code to create a suite is as follow:

    TestSuite *suite = new TestSuite( "MyTestCase" );
    registerTest( suite );

    void registerTest( TestSuite *suite )
    {
        suite->addTest( new TestCaller<MyTestCase>( "test1", test1 ) );
        suite->addTest( new TestCaller<MyTestCase>( "test1", test2 ) );
        ...
    }

    Using the constructor with a pointer on the fixture works:
    void registerTest( TestSuite *suite )
    {

te->addTest( 
                new TestCaller<MyTestCase>( "test1", test1, 
                                                                       new MyTestCase( "file-test1.test") ) ); 
        
suite->addTest( 
                new TestCaller<MyTestCase>( "test1", test2, 
                                                                       new MyTestCase("file-test2.test") ) );
        ...
    }

    The problem is if you want one fixture to be shared with many test caller (which is what you would do when subclassing and reusing test case):

    void registerTest( TestSuite *suite, MyTestCase &fixture )
    {
        suite->addTest( 
                new TestCaller<MyTestCase>( "test1", test1, fixture ) ); 
        suite->addTest( 
                new TestCaller<MyTestCase>( "test1", test2, fixture ) );
        ...
    }

    The problem is who owns the referenced fixture:

    MySubclassedTestCase::suite() {
        TestSuite *suite  = new TestSuite( "MySubClassedTestCase" );

        // WHO owns that fixture ??? => who will delete it ?
        MySubclassedTestCase *fixture = new MySubclassedTestCase();
        MyTestCase::registerTest( suite, *fixture );
        ...
    }
    
    As I see it the problem is solved by introducing a makeFixture() virtual method in test case which can be subclassed. You would have something like:

    void registerTest( TestSuite *suite )
    {
        suite->addTest( 
                new TestCaller<MyTestCase>( "test1", test1, makeFixture() ) ); 
        suite->addTest( 
                new TestCaller<MyTestCase>( "test1", test2, makeFixture() ) );
        ...
    }

    So until a clean way is found to "share" a fixture between test callers, I'll stick to the one fixture per test caller policy (not that much of a bother after all). All the previous problem (subclassing) have been solved by the introduction constructor with a pointer on the fixture.

    The only use I can see for the test caller with fixture by reference is if the Test Caller is stored by value in another class.

    Things to do:
        Update TestSuiteBuilder:
            - add a addTestCaller() method which take a pointer on the fixture.
            - a
dd a constructor that take a pointer on a "makeFixture()" methods, to make
subclassing easier.

    Baptiste.

PS: I tried to login with CVS and SSH this afternoon and I got a error
message. So I guess I'll have to go back to the doc ;-(

---
Baptiste Lepilleur <gai...@fr...>   http://gaiacrtn.free.fr/index.html
Author of The Text Reformatter, a tool for fanfiction readers and writers.
Language: English, French (Well, I'm French).