title: How to get Gradle combined test report?
body: <p>I have multiple test suites configured (as shown below) in my gradle build</p>
  
  <pre>
  task group1(type: Test) {
    useTestNG() {
      includeGroups 'group1'
    }
    // ... some excluded tests
    ext.useDefaultListeners = true
    ext.workingDirectory = 'build/'
    // ... some system properties required by this test
  }
  
  task group2(type: Test, dependsOn: group1) {
    useTestNG() {
      includeGroups 'group2'
    }
    // ... some excluded tests
    ext.useDefaultListeners = true
    ext.workingDirectory = 'build/'
    // ... some system properties required by this test
  }
  
  test.dependsOn group2
  </pre>
  
  <p>When I run the <code>gradle clean build --debug</code>, I could see after every test task (<code>group1</code>, <code>group2</code> etc), gradle deletes the test report and regenerates it. Hence, after the build is done, whatever report I get does not have any information. All blank!</p>
  
  <p>How can I get a combined report?</p>
  
  <p>Thanks,
  NN</p>