OutputStream out

    def setup() {
        out = new ByteArrayOutputStream()
        System.setProperty('mySystemProperty', 'defined in the client JVM')
        buildFile << '''
            tasks.register('printSystemProperty') {
                doLast {
                    System.properties.each { k, v ->
                        println("$k=$v")
                    }
                }
            }
        '''
    }