Gradle - jacoco gradle file that is setup to run tests and create test coverage reports for Android (junit tests or connectedTests...). apply to your project and check "reporting" in gradle tasks. Thanks to https://github.com/artem-zinnatullin/qualitymatters for it.

jacoco.gradle

project.afterEvaluate {
  // Grab all build types and product flavors
  def buildTypes = android.buildTypes.collect { type -> type.name }
  def productFlavors = android.productFlavors.collect { flavor -> flavor.name }

  // When no product flavors defined, use empty
  if (!productFlavors) productFlavors.add('')

  productFlavors.each { productFlavorName ->
    buildTypes.each { buildTypeName ->
      def sourceName, sourcePath
      if (!productFlavorName) {
        sourceName = sourcePath = "${buildTypeName}"
      } else {
        sourceName = "${productFlavorName}${buildTypeName.capitalize()}"
        sourcePath = "${productFlavorName}/${buildTypeName}"
      }
      def testTaskName = "test${sourceName.capitalize()}UnitTest"
      def coverageTaskName = "${testTaskName}Coverage"

      if (project.tasks.findByName(testTaskName) == null) {
        // If the task dont exists bc was disabled dont create the tasks
        return
      }

      // Create coverage task of form 'testFlavorTypeCoverage' depending on 'testFlavorTypeUnitTest'
      task "${coverageTaskName}"(type: JacocoReport, dependsOn: testTaskName) {
        group = 'Reporting'
        description = "Generate Jacoco coverage reports for the ${sourceName.capitalize()} build."

        classDirectories = fileTree(dir: "${project.buildDir}/intermediates/classes/${sourcePath}",
            excludes: ['**/R.class',
                       '**/R$*.class',
                       '**/*$ViewInjector*.*',
                       '**/*$ViewBinder*.*',
                       '**/BuildConfig.*',
                       '**/Manifest*.*',
                       '**/*$Lambda$*.*', // Jacoco can not handle several "$" in class name.
                       '**/*Module.*', // Modules for Dagger.
                       '**/*Dagger*.*', // Dagger auto-generated code.
                       '**/*MembersInjector*.*', // Dagger auto-generated code.
                       '**/*_Provide*Factory*.*'] // Dagger auto-generated code.
        )

        def coverageSourceDirs = ['src/main/java',
                                  "src/$productFlavorName/java",
                                  "src/$buildTypeName/java"]
        additionalSourceDirs = files(coverageSourceDirs)
        sourceDirectories = files(coverageSourceDirs)
        executionData = files("${project.buildDir}/jacoco/${testTaskName}.exec")

        reports {
          xml.enabled = true
          html.enabled = true
        }
      }
    }
  }
}