Running a single test in a reactor

[Dan Fabulich <da...@fabulich.com>]

SUREFIRE-350 suggests that "if test parameter is provided, and no match is 
found, an error should occur, not a successful build with 0 tests."  That 
made sense to me, so I checked in a fix in revision 597952.

However, I discovered that this broke a certain maybe-standard usage: if 
you've got a parent aggregator POM and two children "foo" and "bar" 
running in a reactor, you used to be able to say -Dtest=BarTest; we'd 
compile foo and run no tests in foo, then run BarTest in bar.

This usage very convenient, because you don't have to know that BarTest is 
in the bar module; you can just kick off the tests from the root module 
and run them in whatever module happens to contain them.  You could also 
run multiple individual tests separated by commas in multiple projects.

Now, if you try to run that line from the parent, you'll get a build 
failure in foo, because BarTest isn't defined in foo.

I can think of a number of different possible options here.

1) Leave the code as is.  Just because it's convenient doesn't mean it's 
important and we have to preserve it.

2) Go back and "unfix" SUREFIRE-350.

Notably, in order to fix SUREFIRE-350, I added a new plugin parameter 
called failIfNoTests, which would fail if no tests were run.  (It seemed 
imaginable that somebody would want to turn that on in a variety of cases, 
not just in the -Dtest case.)

If I were to unfix SUREFIRE-350 it'd still be possible to get a build 
failure, if you wanted one really badly, by saying "mvn test 
-Dtest=FooTest -DfailIfNoTests=true".

It's not pretty, but perhaps it's an acceptable compromise.

3) Try to add code that detects the reactor case and handles it.  I think 
it's not that hard to detect whether a given invocation of SurefirePlugin 
is running in a reactor (though I don't actually know how off-hand).  But 
how could I detect the case that this is meant to help, where you 
accidentally had a typo?  There's no way to detect whether a test got run 
*at some point* in the reactor, is there?

-Dan

Re: Running a single test in a reactor

[Brett Porter <br...@apache.org>]

I'd go with (1). I expect it will be clear enough why it's failing so  
people will pick up the new usage fast enough. Can you mention the  
"failIfNoTests=false" flag in the error message? (I assume the true is  
a typo below?)

(3) is a possibility, but you can't really detect if tests are run at  
"some point" as you say other than externally gathering the info in  
surefire by aggregating the results. Sounds like more work than its  
worth.

- Brett

On 11/12/2007, at 7:02 AM, Dan Fabulich wrote:

>
> SUREFIRE-350 suggests that "if test parameter is provided, and no  
> match is found, an error should occur, not a successful build with 0  
> tests."  That made sense to me, so I checked in a fix in revision  
> 597952.
>
> However, I discovered that this broke a certain maybe-standard  
> usage: if you've got a parent aggregator POM and two children "foo"  
> and "bar" running in a reactor, you used to be able to say - 
> Dtest=BarTest; we'd compile foo and run no tests in foo, then run  
> BarTest in bar.
>
> This usage very convenient, because you don't have to know that  
> BarTest is in the bar module; you can just kick off the tests from  
> the root module and run them in whatever module happens to contain  
> them.  You could also run multiple individual tests separated by  
> commas in multiple projects.
>
> Now, if you try to run that line from the parent, you'll get a build  
> failure in foo, because BarTest isn't defined in foo.
>
> I can think of a number of different possible options here.
>
> 1) Leave the code as is.  Just because it's convenient doesn't mean  
> it's important and we have to preserve it.
>
> 2) Go back and "unfix" SUREFIRE-350.
>
> Notably, in order to fix SUREFIRE-350, I added a new plugin  
> parameter called failIfNoTests, which would fail if no tests were  
> run.  (It seemed imaginable that somebody would want to turn that on  
> in a variety of cases, not just in the -Dtest case.)
>
> If I were to unfix SUREFIRE-350 it'd still be possible to get a  
> build failure, if you wanted one really badly, by saying "mvn test - 
> Dtest=FooTest -DfailIfNoTests=true".
>
> It's not pretty, but perhaps it's an acceptable compromise.
>
> 3) Try to add code that detects the reactor case and handles it.  I  
> think it's not that hard to detect whether a given invocation of  
> SurefirePlugin is running in a reactor (though I don't actually know  
> how off-hand).  But how could I detect the case that this is meant  
> to help, where you accidentally had a typo?  There's no way to  
> detect whether a test got run *at some point* in the reactor, is  
> there?
>
> -Dan