android {
:
    buildTypes {
        debug {
            testCoverageEnabled true
        }
    }
}

verification: createDebugCoverageReport

./gradlew createDebugCoverageReport

build/output/code_coverage/debugAndroidTest/connected/{デバイス名}-coverage.ec
build/output/reports/coverage/debug/index.html

:
apply from: './jacoco.gradle' //最終行に追加

apply plugin: 'jacoco'

jacoco {
  toolVersion = "0.8.4" //ツールバージョンを指定可能。省略可。
}

android.applicationVariants.all { variant ->
    def variantName = variant.name.capitalize() //ex. ProdDebug
    def realVariantName = variant.name //ex. prodDebug

    if (variant.buildType.name != "debug") {
        return
    }

    task("jacoco${variantName}TestReport", type: JacocoReport) {
        //AndroidTest後にUnitTestの内容をマージします。
        dependsOn "create${variantName}CoverageReport"
        dependsOn "test${variantName}UnitTest"

        group = "testing"
        description = "Generate Jacoco coverage reports for ${realVariantName}"

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

        //無視するファイル(excludes)の設定を行います
        def fileFilter = ['**/R.class',
                          '**/R$*.class',
                          '**/BuildConfig.*',
                          '**/Manifest*.*',
                          'android/**/*.*',
                          'androidx/**/*.*',
                          '**/Lambda$*.class',
                          '**/Lambda.class',
                          '**/*Lambda.class',
                          '**/*Lambda*.class',
                          '**/*Lambda*.*',
                          '**/*Builder.*'
        ]
        def javaDebugTree = fileTree(dir: "${buildDir}/intermediates/javac/${realVariantName}/compile${variantName}JavaWithJavac/classes", excludes: fileFilter)
        def kotlinDebugTree = fileTree(dir: "${buildDir}/tmp/kotlin-classes/${realVariantName}", excludes: fileFilter)

        def mainSrc = "${project.projectDir}/src/main/java"

        getSourceDirectories().setFrom(files([mainSrc]))
        //Java, Kotlin混在ファイル対応
        getClassDirectories().setFrom(files([javaDebugTree, kotlinDebugTree]))
        getExecutionData().setFrom(fileTree(dir: project.projectDir, includes: [
                '**/*.exec',    //JUnit Test Result
                '**/*.ec'])     //Espresso Test Result
        )
    }
}

dependencies {
:
    testImplementation 'junit:junit:4.12'

    // AndroidX Testing Library (test)
    testImplementation 'androidx.test:core:1.2.0'
    testImplementation 'androidx.test:rules:1.2.0'
    testImplementation 'androidx.test:runner:1.2.0'
    testImplementation 'androidx.test.ext:junit:1.1.1' //ここ
    testImplementation 'androidx.test.ext:truth:1.2.0'
    // AndroidX Testing Library (androidTest)
    androidTestImplementation 'androidx.test:core:1.2.0'
    androidTestImplementation 'androidx.test:rules:1.2.0'
    androidTestImplementation 'androidx.test:runner:1.2.0'
    androidTestImplementation 'androidx.test.ext:junit:1.1.1' //ここ
    androidTestImplementation 'androidx.test.ext:truth:1.2.0'

    // Robolectric
    testImplementation 'org.robolectric:robolectric:4.2'
}

package red.torch.coveragesample

//import androidx.test.runner.AndroidJUnit4
import android.content.Context
import androidx.test.core.app.ApplicationProvider
import androidx.test.ext.junit.runners.AndroidJUnit4
import org.junit.Test
import org.junit.runner.RunWith

import org.junit.Assert.*

/**
 * Instrumented test, which will execute on an Android device.
 *
 * See [testing documentation](http://d.android.com/tools/testing).
 */
@RunWith(AndroidJUnit4::class)
class MainActivityInstrumentedTest {
    @Test
    fun useAppContext() {
        // Context of the app under test.
//        val appContext = InstrumentationRegistry.getTargetContext()
        val appContext = ApplicationProvider.getApplicationContext<Context>()
        assertEquals("red.torch.coveragesample", appContext.packageName)
    }
}

android {
    sourceSets {
        String sharedTestDir = 'src/sharedTest/java'
        test {
            java.srcDir sharedTestDir
        }
        androidTest {
            java.srcDir sharedTestDir
        }
    }
} 

:
    testOptions {
        //Robolectrics: include Android Resource
        unitTests.includeAndroidResources = true
        //Robolectrics: No Verify for Java 8
        unitTests.all {
            jvmArgs '-noverify' //ここを追加
        }
    :

 -noverify
クラスがバイトコードの検証なしにロードされます。このオプションを使用するには、oracle.aurora.security.JServerPermission(Verifier)を付与されていることが必要です。このオプションを効果的にするには、-resolveと併用する必要があります。