JUnit4を使ったテスト

build.gradle

apply plugin: 'com.android.application'

android {
    compileSdkVersion 22
    buildToolsVersion "22.0.1"

    defaultConfig {
        applicationId "com.unuuu.myapp"
        minSdkVersion 14
        targetSdkVersion 22
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner 'android.support.test.runner.AndroidJUnitRunner'
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }

    packagingOptions {
        exclude 'LICENSE.txt'
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:22.2.0'

    androidTestCompile 'com.android.support.test:testing-support-lib:0.1'
    androidTestCompile 'org.hamcrest:hamcrest-library:1.3'
}

MainActivityTest.java

package com.unuuu.myapp;

import android.support.test.runner.AndroidJUnit4;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;

import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.is;

@RunWith(AndroidJUnit4.class)
public class MainActivityTest {
    @Before
    public void setUp() throws Exception {
    }

    @Test
    public void テストのテスト() {
        assertThat("hoge", is("hoge"));
    }

    @After
    public void tearDown() throws Exception {
    }
}