Where should I put test support code for a Java library

Question

I have a Maven project which is used as a library in other projects. The setup is pretty standard: src/main with the library code, src/test with te

Answer 1

Here is a POM fragment which splits the main JAR into the normal artifact and a "JUnit support JAR":

    
        
            maven-jar-plugin
            
                
                    default-jar
                    package
                    
                        jar
                    
                    
                        
                            true
                            
                                true
                            
                        
                        
                            **/junit/**
                        
                    
                

                
                    junit-jar
                    package
                    
                        jar
                    
                    
                        junit
                        
                            true
                            
                                true
                            
                        
                        
                            **/junit/**
                        
                    
                

                
                    test-jar
                    
                        test-jar
                    
                
            
        

    

In a nutshell, it looks for any package with junit in its name and puts it into the JUnit JAR, excluding it from the normal artifact.

If the coordinate for the normal jar is

com.group
foo

then you can get the JUnit support code by simply adding junit:

com.group
foo
junit

So to use this, the POM which depends on com.group:foo will look like this:

    com.group
    foo
    ...


    com.group
    foo
    ...
    junit
    test

Sometimes, you will need JUnit to compile your "JUnit support JAR". If that's the case, use

    junit
    junit
    compile
    true

to include JUnit into the build. This will make the dependency available at compile time but it will not leak to anyone else.