RFC: idea to distribute test harness for plugin developers

[spotbugs]

RFC: idea to distribute test harness for plugin developers

[jsotuyod]

I love this! I've been thinking about it for some time.

It would split the codebase making it more mantainable, it would allow third parties to use the test infrastructure AND it allows plugin developers to easily run just their detectors without the defaults ones.

Also of note, it forces ourselves to respect the public API provided by the core, making it more obvious if we ever break anything for third parties.

As far as I'm concerned, feel free to push this forward as part of our project structure changes.

[KengoTODA]

I will list "core" classes which is depending on detector:

findbugs/src/main/java/edu/umd/cs/findbugs/FindBugs2.java:import edu.umd.cs.findbugs.detect.NoteSuppressedWarnings;
findbugs/src/main/java/edu/umd/cs/findbugs/ba/AnalysisContext.java:import edu.umd.cs.findbugs.detect.UnreadFields;
findbugs/src/main/java/edu/umd/cs/findbugs/ba/AnalysisContext.java:import edu.umd.cs.findbugs.detect.UnreadFieldsData;
findbugs/src/main/java/edu/umd/cs/findbugs/ba/FieldSummary.java:import edu.umd.cs.findbugs.detect.UnreadFieldsData;
findbugs/src/main/java/edu/umd/cs/findbugs/ba/XFactory.java:import edu.umd.cs.findbugs.detect.BuildObligationPolicyDatabase;
findbugs/src/main/java/edu/umd/cs/findbugs/ba/vna/ValueNumberFrameModelingVisitor.java:import edu.umd.cs.findbugs.detect.FindNoSideEffectMethods.MethodSideEffectStatus;
findbugs/src/main/java/edu/umd/cs/findbugs/ba/vna/ValueNumberFrameModelingVisitor.java:import edu.umd.cs.findbugs.detect.FindNoSideEffectMethods.NoSideEffectMethodsDatabase;
findbugs/src/test/java/edu/umd/cs/findbugs/ba/ch/Subtypes2Test.java:import edu.umd.cs.findbugs.detect.FindRefComparison;

It seems difficult to move all detectors to new sub module, I will move a part of them.