Custom Gradle Test Task For Android

Problem

I want to create a custom gradle test task to only run JUNIT tests and omit Robolectric tests. I am attempting to achieve this task by creating a new test annotation and omitting any tests that include that new annotation.

Error

JUNIT packages are not included when I run the the gradle task.

error: package android.test.suitebuilder.annotation does not exist
import android.test.suitebuilder.annotation.SmallTest;

Details

New Annotation

@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD, ElementType.TYPE})
public @interface RobolectricTest {
}

Gradle File

apply plugin: 'com.android.application'
apply plugin: 'com.google.gms.google-services'

repositories {
    mavenCentral()
    maven { url     'http://ift.tt/1eR8uok' }
    maven { url 'http://ift.tt/1ca5iuY' }
}

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.google.gms:google-services:1.3.0-beta1'
    }
}

android {
    compileSdkVersion rootProject.ext.compileSDKVersion
    buildToolsVersion rootProject.ext.buildToolsVersion

    defaultConfig {
        applicationId "com.example"
        minSdkVersion 17
        targetSdkVersion rootProject.ext.targetSdkVersion
        buildConfigField "String", "BUILD_TIME", "\"" + getDateAndTime() + "\""
        buildConfigField "String", "VERSION_BUILD", "\"" +     project["VERSION_BUILD"] + "\""
        versionCode Integer.parseInt(project.VERSION_CODE)
        versionName project.VERSION_NAME
    }

    signingConfigs {
        debug {
            storeFile file(project.DEBUG_KEYSTORE)
            storePassword project.DEBUG_KEYSTORE_PASSWORD
            keyAlias project.DEBUG_KEYSTORE_ALIAS
            keyPassword project.DEBUG_KEY_PASS
        }

        release {
            storeFile file(project.RELEASE_KEYSTORE)
            storePassword project.RELEASE_KEYSTORE_PASSWORD
            keyAlias project.RELEASE_KEYSTORE_ALIAS
            keyPassword project.RELEASE_KEY_PASS
        }
    }

    sourceSets {
        main {
            res.srcDirs = ['src/main/res/',
                           'src/main/abc']
        }
    }

    buildTypes {
        release {
            minifyEnabled true
            shrinkResources true
            zipAlignEnabled true
            proguardFile getDefaultProguardFile('proguard-android-optimize.txt')
            proguardFile 'proguard-rules.pro'
            signingConfig signingConfigs.release

        }
        debug {
            testCoverageEnabled = true
            debuggable true
            signingConfig signingConfigs.debug
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])

    testCompile ('junit:junit:4.12')
    testCompile ('org.apache.maven:maven-ant-tasks:2.1.3')
    testCompile ('org.robolectric:robolectric:3.0')
    testCompile ('org.robolectric:shadows-support-v4:3.0')
}

sourceSets {
    unitTest {
        java.srcDirs = ['src/test/java']
        resources.srcDirs = ['src/test/resources']
    }
}

ClassLoader getClassLoader() {
    List urls = sourceSets.test.runtimeClasspath.collect {
        it.toURI().toURL()
    }
    return URLClassLoader.newInstance( urls as URL[] )
}    

/**
 *  Filters out files that have specific annotation
 * @param map - map of things to filter
 * @return - list of acceptable files after filter
 */
List annotationFilter( Map map ) {
   map.prefix = map?.prefix ?: '' // prefix: provide convenience for passing in annotation names

    ClassLoader loader = classLoader
    List result

    // filter with annotations
    if( !map.includes ) {
        result = map?.names
    } else {
        result = []
        map?.names.each { name ->
            Class klass = loader.loadClass( name )
            map?.includes.each { annotationName ->
                String fullName = map.prefix + annotationName
                Class annotation = loader.loadClass( fullName ).asSubclass( Annotation )
                if( !klass.isAnnotationPresent( annotation ) ) {
                    result << name
                }
            }
        }
    }

    if( result?.size() == 0 ) result = [ 'no.tests.to.run' ]
    return result
}

/**
 * Gradle task to run only robolectric tests.
 */
task unitTest( type: Test, description: 'Run all junit tests' ) {

    android.sourceSets.main.java.srcDirs.each { dir ->
        def buildDir = dir.getAbsolutePath().split('/')
        buildDir =  (buildDir[0..(buildDir.length - 4)] + ['build',     'classes', 'debug']).join('/')


        sourceSets.unitTest.compileClasspath += files(buildDir)
        sourceSets.unitTest.runtimeClasspath += files(buildDir)
    }

    testClassesDir = sourceSets.unitTest.output.classesDir
    classpath = sourceSets.unitTest.runtimeClasspath

    doLast {
        println "Doing Last"
        List names = testClassNames()
        List filtered = annotationFilter( names: names, includes:   ['testUtils.RobolectricTest'] )
        println 'Running ' + filtered.size() + ' tests:\n' +     filtered*.toString()*.replaceAll('^','\t').join('\n')

       filter {
            setIncludePatterns( filtered as String[] )
        }
    }
}