我正在使用带有gradle 1.12的Android Studio 0.6.1

这是我的文件夹结构：

MyActivityTest.java

package com.vist.testableapp.tests;

import android.content.Intent;
import android.test.ActivityUnitTestCase;
import android.test.suitebuilder.annotation.SmallTest;
import android.widget.Button;

import com.vist.testableapp.MyActivity;
import com.vist.testableapp.R;

public class MyActivityTest extends ActivityUnitTestCase<MyActivity>
{
    public MyActivityTest(Class<MyActivity> activityClass)
    {
        super(activityClass);
    }
    Button btn1;

    @Override
    public void setUp() throws Exception
    {
        super.setUp();

        startActivity(new Intent(getInstrumentation().getTargetContext(),MyActivity.class),null,null);
        btn1 = (Button)getActivity().findViewById(R.id.button1);
    }

    @SmallTest
    public void testFirst()
    {
        assertEquals("Btn1",btn1.getText());
    }
}

应用程序的build.gradle

apply plugin: 'android'

android {
    compileSdkVersion 19
    buildToolsVersion "19.1.0"

    defaultConfig {
        applicationId "com.vist.testableapp"
        minSdkVersion 15
        targetSdkVersion 15
        versionCode 1
        versionName "1.0"
        testApplicationId "com.vist.testableapp.tests"

    }
    buildTypes {
        release {
            runProguard false
            proguardFiles getDefaultProguardFile('proguard-android.txt'),'proguard-rules.pro'
        }
    }
}

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

任何人都可以指出我做错了什么或我错过了什么？
我搜索过,但没有一个答案对我有帮助.