custom test task

task runTests(type: JavaExec, dependsOn: 'testClasses') {
    main = 'org.testng.TestNg'
    classpath = files("./src/test/resources",
                      project.sourceSets.main.compileClasspath,
                      project.sourceSets.test.compileClasspath,
                      project.sourceSets.main.runtimeClasspath,
                      project.sourceSets.test.runtimeClasspath)
    args = ["-parallel",  "methods", "-threadcount", "1", "-d", "./build/test-output", "./src/test/resources/masterSuite.xml"]
}