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From George Harley1 <GHAR...@uk.ibm.com>
Subject Re: Test suite layout
Date Mon, 16 Jan 2006 13:25:55 GMT
Hi Geir, 

Reading "The Da Vinci Code" is common practice too. Doesn't make it a good 
book. 

I wasn't trying to say that it is a bad practice in every case, just that 
it does have its downsides and for that reason the assertion that "unit 
test code must reside in the same package as the classes" is not correct. 
It is possible to arrive at a high quality set of unit tests for a class 
where the package names differ. 

In the interests of avoiding any religious war can I just say that there 
is no religious war here : both unit test approaches work but neither 
should we look on one as being "the only way". So let's not argue about it 
on the list. Instead, let's see how the unit test code evolves over time 
before drawing any conclusions. 

Best regards, 
George
________________________________________
George C. Harley




Geir Magnusson Jr <geir@pobox.com> 
16/01/2006 12:54
Please respond to
harmony-dev@incubator.apache.org


To
harmony-dev@incubator.apache.org
cc

Subject
Re: Test suite layout








George Harley1 wrote:
> Hi, 
> 
>> This is not the goal of unit tests. They do not test API, they test the 

> code,
>> including package-access members etc. That is why unit tests must 
reside
>> in the same package as the classes.
> 
> This is radical stuff. I have never heard the argument before that unit 
> tests *must* share the same package name as the type under test. One 
> important reason why many think it is a bad idea to take this approach 
is 
> that the resulting unit test code becomes too closely coupled with the 
> code under test.

Huh?  It's a common practice - it gives the unit test the ability to 
really test the implementation because it has package level priv.

> 
> Think about it ... 
> 
> If unit test code can access every package-access member and method in a 

> given type then the test code will eventually reach a point where it 
> contains a lot of brittle assumptions about internal implementation. 

It can, yes.  OTOH, it is testing internal private methods, so yes, 
there's going to be those assumptions built in.

> Consequently, when implementation changes occur, the corresponding test 
> code will break. Note : I'm not talking about API changes breaking the 
> test code here, I'm talking about changes to protected and 
package-access 
> stuff which - by definition - the developer has chosen to keep 
non-public. 

Right - and the unit tests test that code.  How else do you test it in a 
fine-grained way?  Only via public methods?


> So as the internals change the unit tests break. And further internal 
> changes make the unit tests break. And ultimately maintaining the tests 
> with close-coupling to the internals of the type under test becomes a 
bit 
> of a pain and their overall value in the test harness diminishes because 

> minor refactorings to the type-under-test now take so darned long to 
carry 
> out. 

But it gives you very fine-grained coverage, if you want that.

geir

> 
> 
> Best regards, 
> George
> ________________________________________
> George C. Harley
> 
> 
> 
> 
> 
> Mikhail Loenko <mloenko@gmail.com> 
> 16/01/2006 11:58
> Please respond to
> harmony-dev@incubator.apache.org
> 
> 
> To
> harmony-dev@incubator.apache.org
> cc
> 
> Subject
> Re: Test suite layout
> 
> 
> 
> 
> 
> 
> On 1/16/06, Tim Ellison <t.p.ellison@gmail.com> wrote:
> ...
>> If your unit tests are intended to test API, then they should be 
calling
>> the API in the same manner that an application will call the API.  Just
> 
> This is not the goal of unit tests. They do not test API, they test the 
> code,
> including package-access members etc. That is why unit tests must reside
> in the same package as the classes.
> 
> Other kinds of tests like compatibility or functional tests call just
> public and protected methods so they can be in different packages.
> 
> Thanks,
> Mikhail Loenko
> Intel Middleware Products Division
> 
> 
> 
> 
> 
>> look at the number of places where we check to see if the classloader 
==
>> null to see where this matters.
>>
>>> Some of them may depend on security manager component if
>>> you like to run a test in some security restricted environment. But it
>>> is not a big issue: the security manager component can be configured
>>> dynamically and you should install your custom security manager before
>>> running a test.
>> Yes, we should do that on the application classloader to test security
>> manager functionality.
>>
>> Regards,
>> Tim
>>
>>> What do you think?
>>>
>>> Thanks,
>>> Stepan Mishura
>>> Intel Middleware Products Division
>>>
>>>
>>>> -----Original Message-----
>>>> From: Tim Ellison [mailto:t.p.ellison@gmail.com]
>>>> Sent: Thursday, January 12, 2006 8:04 PM
>>>> To: harmony-dev@incubator.apache.org
>>>> Subject: Re: Test suite layout
>>>>
>>>> Geir Magnusson Jr wrote:
>>>>
>>>>> Tim Ellison wrote:
>>>> <snip>
>>>>
>>>>>> We would have written it as java.io.tests, but the java.<whatever>
>>>>>> namespace is reserved, so the formula is simply
>>>>>>
>>>>>> <package>.<type>  -> org.apache.harmony.tests.<package>.<type>Test
>>>>>
>>>>> Ug - then you have the problem of not being in the namespace as what
>>> you
>>>
>>>>> are testing.
>>>>>
>>>>> THat's why people use parallel trees - so your test code is
>>> physically
>>>
>>>>> separate but you have freedom of package access.
>>>> For 'normal' application code then you can do this, but since we are
>>>> writing the java packages themselves then you come unstuck because 
the
>>>> java packages have to run on the bootclasspath, and the tests on the
>>>> application classpath.
>>>>
>>>> You don't want to run all your tests on the bootclasspath (because 
> then
>>>> it would not be subject to the same security sandboxing as 
> applications
>>>> using the APIs you are testing); and you cannot put java.<whatever>

on
>>>> the application classpath because the VM will catch you out (you'd 
get
>>> a
>>>
>>>> linkage error IIRC).
>>>>
>>>>
>>>>>> This makes it clear what is being tested, and where to add new 
tests
>>>> etc.
>>>>
>>>>> So would
>>>>>
>>>>>  test/org/apache/harmony/io/TestFoo.java
>>>>>
>>>>> (to test something in org.apache.harmony.io, and arguable to test 
the
>>>>> Foo.java class in there.  (or TestFoo.java - it's early - no coffee
>>> yet)
>>>
>>>> Not sure what you are saying here... For java.<whatever> packages we
>>>> need a prefix on the test packages to keep the VM happy, but for
>>>> org.apache.harmony packages we can have either pre- or post-.
>>>>
>>>> I'd actually prefer a postfix of .tests for non-API packages, though 
I
>>>> can understand if people object to the inconsistency; so
>>>>
>>>> org.apache.harmony.tests.java.io.FileTest.java      <- test API
>>>> org.apache.harmony.io.tests.FileImpltest.java  <- test public methods
>>>>                                                 in our IO impl'
>>>>
>>>>
>>>>> Simiarly
>>>>>
>>>>>  test/java/util/TestMap.java
>>>>>
>>>>>
>>>>>> Then within the test class itself the methods are named after the
>>> method
>>>
>>>>>> under test, with a familar JNI-style encoding,  so we have things
>>> like:
>>>
>>>>>> org.apache.harmony.tests.java.io.FileTest contains
>>>>>>    public void test_ConstructorLjava_io_FileLjava_lang_String() {
>>>>>>    ...
>>>>>>    }
>>>>>>
>>>>>> and
>>>>>>
>>>>>> org.apache.harmony.tests.java.lang.FloatTest contains
>>>>>>    public void test_compareToLjava_lang_Float() {
>>>>>>    ...
>>>>>>    }
>>>>>
>>>>> ...or whatever the convention is for JUnit.  I think that's one of
>>> the
>>>
>>>>> nice things about TestNG, is that it's annotated, so you have the
>>>>> freedom there.
>>>>>
>>>>>
>>>>>> If the test is added due to a regression, then it is put into the
>>> right
>>>
>>>>>> place in the test suite, and flagged with a comment (i.e. a
>>> reference to
>>>
>>>>>> the Harmony JIRA number).
>>>>>
>>>>> Yes - and I'd even advocate a parallel directory there too so that
>>> it's
>>>
>>>>> clear that the regressions are different, but whatever.  The only
>>> snag
>>>
>>>>> there is name collision with the classes.
>>>> I thought we'd agreed that 'regression' was not a useful 
> classification
>>>> within the test suite layout ...
>>>>
>>>>
>>>>> I think that a simple comment is enough.  If we want to get cute,
>>> maybe
>>>
>>>>> a javadoc tag so we can manage mechanically in the future.
>>>> ok -- do you have a usecase in mind?
>>>>
>>>> Regards,
>>>> Tim
>>>>
>>>>
>>>>
>>>>>> George Harley1 wrote:
>>>>>>
>>>>>>
>>>>>>> Hi,
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>> I think that regression tests should be marked in some way.
>>>>>>>
>>>>>>>
>>>>>>> Agreed.  But can we please *resist* the temptation to do this
by
>>>>>>> incorporating JIRA issue numbers into test case names (e.g. 
calling
>>>>>>> unit test methods test_26() or test_JIRA_26()). I've seen this

kind
>>>>>>> of approach adopted in a couple of projects and, in my experience,
>>> it
>>>
>>>>>>> often leads to the scattering of duplicated test code around
the
>>> test
>>>
>>>>>>> harness.
>>>>>>>
>>>>>>> Better, methinks, to either create a new test method with a
>>>>>>> meaningful name or else augment an existing method - whatever

makes
>>>>>>> more sense for the particular issue. Then marking certain code
as
>>>>>>> being for regression test purposes could be done in comments
that
>>>>>>> include the URL of the JIRA issue. Perhaps an agreed tag like
>>> "JIRA"
>>>
>>>>>>> or "BUG" etc could be used as an eye-catcher as well ?
>>>>>>> e.g.
>>>>>>> // BUG http://issues.apache.org/jira/browse/HARMONY-26
>>>>>>>
>>>>>>>
>>>>>>> My 2 Euro Cents.
>>>>>>> Best regards, George
>>>>>>> ________________________________________
>>>>>>> George C. Harley
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> "Mishura, Stepan M" <stepan.m.mishura@intel.com> 12/01/2006
04:56
>>>>>>> Please respond to
>>>>>>> harmony-dev@incubator.apache.org
>>>>>>>
>>>>>>>
>>>>>>> To
>>>>>>> <harmony-dev@incubator.apache.org>
>>>>>>> cc
>>>>>>>
>>>>>>> Subject
>>>>>>> RE: regression test suite
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> Hello,
>>>>>>> Tim Ellison wrote:
>>>>>>> [snip]
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>> What is the useful distinction for regression tests being
kept
>>>>>>>
>>>>>>> separate?
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>> I can see that you may distinguish unit and 'system-level'
tests
>>> just
>>>
>>>>>>>> because of the difference in frameworks etc. required, but
why do
>>> I
>>>
>>>>>>> care
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>> if the test was written due to a JIRA issue or test-based
>>> development
>>>
>>>>>>> or
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>> someone who get's kicks out of writing tests to break the
code?
>>>>>>>>
>>>>>>>
>>>>>>> I agree that separating regression tests doesn't make sense.
>>>>>>> However I think that regression tests should be marked in some

way.
>>>>>>> This will signal a developer that a test was created to track
>>> already
>>>
>>>>>>> known issue. IMHO, a regression test should point out to a bug
>>> report
>>>
>>>>>>> and a bug report (after resolving a bug) should contain a 
reference
>>> to
>>>
>>>>>>> corresponding regression test in repository.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Stepan Mishura
>>>>>>> Intel Middleware Products Division
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>> --
>>>>
>>>> Tim Ellison (t.p.ellison@gmail.com)
>>>> IBM Java technology centre, UK.
>>>
>> --
>>
>> Tim Ellison (t.p.ellison@gmail.com)
>> IBM Java technology centre, UK.
>>
> 
> 
> 



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