jacoco task for espresso coverage

build.gradle

apply plugin: 'jacoco'
jacoco {
    version "0.7.1.201405082137"
}

task jacocoTestReportAndroidTest(type: JacocoReport, dependsOn: "connectedAndroidTest") {
    def coverageSourceDirs = [
            'src/main/java'
    ]
    group = "Reporting"
    description = "Generates Jacoco coverage reports"
    reports {
        csv.enabled false
        xml{
            enabled = true
            destination "${buildDir}/reports/jacoco/jacoco.xml"
        }
        html{
            enabled true
            destination "${buildDir}/jacocoHtml"
        }
    }
    classDirectories = fileTree(
            dir: 'build/intermediates/classes',
            excludes: ['**/R.class',
                       '**/R$*.class',
                       '**/BuildConfig.*',
                       '**/Manifest*.*',
                       '**/*Activity*.*',
                       '**/*Fragment*.*'
            ]
    )
    sourceDirectories = files(coverageSourceDirs)
    additionalSourceDirs = files(coverageSourceDirs)

    if (project.hasProperty('coverageFiles')) {
        // convert the comma separated string to an array to create an aggregate report from
        // multiple coverage.ec files
        def coverageFilesArray = coverageFiles.split(',')
        executionData = files(coverageFilesArray)
    }
    else {
        executionData = files('build/outputs/code-coverage/connected/coverage.ec')
    }
}