pipeline
{
    agent any

    stages
    {
        stage ('Parallel')
        {
            steps
            {
                parallel(
                    first:  
                    {
                        sh "run_first_test_that_outputs" // In our case PHPUnit                                               
                    }
                    second:
                    {
                        sh "run_second_test_that_outputs" // In our case, session based tests                                 
                    }
                )
            }
        }
    }
}