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From "Anton Avtamonov" <anton.avtamo...@gmail.com>
Subject Re: [classlib] How to test serialization? (was: [classlib] Tests for serialization – which package, name?)
Date Tue, 02 May 2006 09:21:25 GMT
Stepan.
Let me answer you shortly: yes, my main concern is about an assetion step.
Just because I saw too many classes without specified serialization
form, without equals() and so on. Actually, I suppose that is the
entire graphical framework (awt + Swing) which is definitely more then
5% :-). I didn't deep investigations of course, but suppose that the
simple assertion approach would not work there. Just because it will
require to compare specific fields rather than call assertEquals().

About third scenario with IOException.
If IOException is the only possible reaction for incorrect form then
you are right: we don't need any specific checks.

--
Anton Avtamonov,
Intel Middleware Products Division


On 5/2/06, Stepan Mishura <stepan.mishura@gmail.com> wrote:
> On 5/2/06, Anton Avtamonov wrote:
> >
> > On 5/2/06, Stepan Mishura wrote:
> > > Mikhail,
> > >
> > > You are right - I think I asked not proper question. The base issue is:
> > how
> > > we are going to test serialization and what support from testing
> > framework
> > > is required? So far we have two serialization frameworks. Roughly, the
> > first
> > > framework provides utility class with set of static methods and the
> > second
> > > one provides super class to be extended.
> > >
> > > Let's understand what kind of serialization tests are required.
> > > 1) Compatibility: testing scenario - serialize a number of a class'
> > objects
> > > on RI to get a set of golden files, create test to verify that
> > > deserialization of golden files produces expected objects on Harmony
> > > implementation. I think that everybody agree that this scenario is
> > required
> > > for every serializable class.
> >
> > Agree. The only exception is those cases when serialization form is
> > not documented and cannot be implemented as in RI.
> >
> > >
> > > 2) Self testing: testing scenario is to verify that an object can be
> > > serialized/deserialized smoothly on Harmony implementation. Again this
> > > scenario is also required for every serializable class.
> >
> > Agree.
> >
> > >
> > > 3) Error: testing scenario is to check that deserialization of corrupted
> > > serial form results in IOException, for example, if a class has fields
> > > startDate and endDate then class implementation should verify that
> > startDate
> > > < endDate after deserialization. This scenario is not required for every
> > > class.
> >
> > Yes. This requires both corrupted ser forms and assertion customization.
>
>
> Sorry, I didn't catch - what assertion customization is required in case of
> IOException?
>
> >
> > > Are there any others testing scenarios?
> > >
> > > I think that this is obvious that 1 and 2 scenarios need support from
> > > testing framework. Let's review what support we currently have:
> > > --- compatibility testing scenario:
> > > If you use the first framework then you have explicitly add to each test
> > for
> > > serializable class a separate method and use utility methods to perform
> > > testing, for example,
> > > public void serializationCompatibility() {
> > >    SerializationTester.assertCompabilityEquals(new MyClass(), "
> > > MyClassFile.ser");
> > > }
> > >
> > > In case of the second framework a test inherits method testGolden() that
> > > does standart testing routine: for each object returned by getData()
> > method
> > > it finds corresponding golden file, deserializes it and compares with
> > the
> > > object.
> >
> > You forgot to mention the comparison method which may have to be
> > overriden as well in case:
> > - RI serialzaition differ
>
>
> How many such cases? I expect that there should be no more then 3-5% of
> overall amount of  serializable classes. Should we base serialization
> testing framework design on such rare cases? I think no. Also IMHO that such
> cases may be resolved by overriding testGolden() method and putting all
> specific to this method.
>
> - you need to check the state of transient fields
>
>
> Most of them are private, right? So you will check them via public API?
>
> - equals() method is not defined for the type or not covers all the
> > fields. In this case you have to provide 'manual' comparison (very
> > often case, IMHO)
>
>
> IMHO this is the right approach to have separate comparision method that is
> differ from other assert methods to compare object in case of
> serialization/deserialization testing. So if you have to perform 'manual'
> comparison in any case then it would be better to do it in separate
> and standartized assert method. IMHO, assertDeserialized is a proper name
> for such method. Also this is very often case for Exception classes so we
> can generalize this case in super class too.
>
>
>
> > >
> > >  --- self testing scenario:
> > > Similar to compatibility scenario: using the first framework you have
> > > explicitly add a separate testing method:
> > > public void testSerialization() {
> > >    assertTrue(SerializationTester.assertEquals(new SomeSerializable()));
> > > }
> > >
> > > In case of the second framework a test inherits testSelf() does the
> > > following testing routine: for each object returned by getData() method
> > it
> > > serializes/deserializes the object and compares with the initial object.
> >
> > Again, you have to provide comparison customization. Besides, it may
> > differ from comparison for the golden form. So, to cover everything
> > you have to define two comparison methods in your framework: for
> > golden comparison and for self-comparison.
>
>
> Is this theoretical thought or you have concrete example?
>
> >
> > > To summarize: for the first framework it is required to add explicitly
> > at
> > > least two testing methods to each test.
> >
> > Yes. And allows to do all the particular asserions (fields comparison)
> > right in the test. At the other hand, if the comparison is 'default',
> > you just need assertEquals().
> >
> > The second framework uses
> > > inheritance mechanism so two standart testing methods are inherited from
> > > super class and you only have to implement getData() abstract method.
> >
> > This is really convenient for the simple cases when you don't have to
> > customize the assertion step.
> >
> > >
> > > IMHO, as far as it is possible to unify serialization testing I think
> > that
> > > inheritance appoach makes sense - two standart testing methods, less
> > > copied/pasted code that leads to more maintainable tests.
> >
> > As I said before, second approach can result in less code since some
> > TestCases will just override one-two methods. However I disagree about
> > maintanability - the inheritance approach is much less flexible (see
> > above).
>
>
> So the main disadvantage for you is assertion step, right?
>
> --
> Thanks,
> Stepan Mishura
> Intel Middleware Products Division
>
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