modulepath and classpath mixture

[Alan Bateman]

On 30/03/2016 13:28, Russell Gold wrote:
> :
>
>
> So if the tests and main code are both in directories, which they have been up to now in Maven, why would there be a problem? Both would be in the unnamed module and able to access one another.
>
There shouldn't any issue there, it should just work as it has always done.

The thread here has meandered a bit but I think the scenario under 
discussion is tests for a module that need to nestmate with the module 
under test. The tests are in their own test tree. The tests are compiled 
separately from the module they test and may have additional dependences 
(such as on TestNG or JUnit for example). When compiling or running then 
the tests need to access public types in non-exported packages and maybe 
package private members too. The support for this has been in jake for a 
long time but involves command line options that many developers or 
build environments won't immediately grok. In particular the tests have 
to be compiled "as if" they augment the already compiled module - that 
is what javac -Xmodule is about. There is no need to co-locate source 
files or class files of course. When run then the -Xpatch option is what 
brings the tests and the module classes together. If we get the tools 
right then most developers won't ever see this of course.

One other thing to say that we've already been through some of this with 
the JDK tests. The jtreg test harness that we use for the JDK tests has 
been updated (thanks to Jon Gibbons) with useful support for modules 
[1]. It's enough for us to write tests that use JDK-internal APIs or 
write tests that nestmate with types in system modules so that they get 
access to package private type or public types in non-exported packages. 
It has rudimentary support for user modules too. Additional dependences 
are still an issue but our tests don't require additional dependences 
beyond TestNG. The test harness employs a bit of hackery to get things 
done, important when starting out, but I expect will go away in time.

-Alan.

[1] 
http://hg.openjdk.java.net/code-tools/jtreg/raw-file/tip/src/share/doc/javatest/regtest/tag-spec.html