Separate integration test task on gradle with android

Question

I want to run tests that have the 'integration' word in the path to be excluded with the default test run, but I want to run them all together in a separate task. Currently I have a basic test configuration:

sourceSets {
    androidTest.setRoot('src/test')

    integrationTest.setRoot('src/test')
}

...

androidTestCompile 'junit:junit:4.11'
androidTestCompile 'com.jayway.android.robotium:robotium-solo:5.1'
androidTestCompile files('libs/android-junit-report-1.5.8.jar')
androidTestCompile 'com.squareup:fest-android:1.0.8'
androidTestCompile 'org.robolectric:robolectric:2.3'

integrationTestCompile 'junit:junit:4.11'
integrationTestCompile 'com.jayway.android.robotium:robotium-solo:5.1'
integrationTestCompile files('libs/android-junit-report-1.5.8.jar')
integrationTestCompile 'com.squareup:fest-android:1.0.8'
integrationTestCompile 'org.robolectric:robolectric:2.3'

...

androidTest {
    include '**/*Test.class'
    exclude '**/espresso/**/*.class'
    exclude '**/integration/**'
}

task integrationTest(type: Test) {
    include '**/integration/**'
}

This causes an error while syncing gradle in AS:

Warning: project ':ProjectName': Unable to resolve all content root directories
Details: java.lang.NullPointerException: null

but if I remove the integrationTest task it doesn't occur. Also with the task present I am able to run the 'integrationTest' task but this causes another error:

Error:Could not determine the dependencies of task ':ProjectName:integrationTest'.
A base directory must be specified in the task or via a method argument!

Answer 1

It isn't entirely obvious, but this error is caused by not defining testClassesDir in your task definition.

task integrationTest(type: Test) {
    include '**/integration/**'
    testClassesDir = file('build/intermediates/classes')
}

Something similar is described in the Gradle User Guide for the Java plugin, but it doesn't entirely translate to the Android plugin. I haven't worked out all of the particulars just yet, but I will update this answer as I figure it out.