[WIP] [MPLUGINTESTING-93] - Prepare documentation / examples for JUnit 5 and Maven 3

[aamotharald]

starting some documentation activities now and performing testing of the JUnit5 maven-plugin testing capabilities with existing open source maven plugins.

@gnodet I have made a small change in the MojoExtension as I think it's valid to have no configuration for your maven plugin at all. I'll just take the commit away if my understanding here is wrong

[slachiewicz]

this may collide with Maven 4 apis

[aamotharald]

Hi @slachiewicz ,
yes this might collide and this I am doing by intent.
Consider the following use case:
Somebody uses @InjectMojoon maven version 3 and creates JUnit Jupiter test cases to test his/her Mojo.

Then he/she decides to migrate to Maven4.
As the codelines differ between maven3/maven4, there might be glitches / issues. But the migration will be a lot less cumbersome if you don't have to rename all the imports just because the package changes from maven3 to maven4. This is why I would like to have the same Packages on Maven3/4.
Does that make sense or should we strictly separate the packages and make the maven3-4 migration cumbersome for the consumers?

PS: I made some experiments and at least for my limited use cases the migration from maven3 to 4 with this setup went really smooth. Still thinking how to deal with One Exception which got relocated between 3 to 4 which I plan to provide some further solution.

[gnodet]

This is really interesting.
I'd like to see some changes from c6ef221 back ported to make the annotations identical (the @Inherited and the changes in InjectMojo).
Maybe also the new @Basedir annotation ?

[aamotharald]

Hi @gnodet ,
I have been able to to make the Annotations identical (added @Inherited and removed the boolean flag from InjectMojo).
I was also able to backport the @Basedir Annotation and added a unit test for that behaviour.

So what's left open is the stubbing. I made a check and backporting all the stubs seems to be a bigger task. My current opinion is to NOT offer the stubs on maven 3 (which means maven-plugin-testing with stubs is only possible with old JUnit 4 style tests extending the AbstractMojoTestCase). What is your opinion there?