本文主要介紹在android studio中進行單元測試的方式蜗顽，你將了解到
1.如何在android studio中引用JUnit4
2.單元測試Demo

引用模塊

然后在build.gradle中添加

compile 'com.jakewharton.espresso:espresso:1.1-r3'~~~

Demo
新建一個Calculator 測試它的方法

package com.example.news;

/**

• Created by 小新 on 2016/7/1.
  */
  public class Calculator {
  public double sum(double a, double b){
  return a+b;
  }

  public double substract(double a, double b){
  return a-b;
  }

  public double divide(double a, double b){
  return a/b;
  }

  public double multiply(double a, double b){
  return a*b;
  }

  public double addMore(double a,double b,double c){

   return a+b+c;
  

  }

}

在類名上面點擊右鍵生成test測試類

![測試類生成截圖](http://upload-images.jianshu.io/upload_images/796164-f98d82421be0796a.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)

![測試類名种樱，勾選測試方法](http://upload-images.jianshu.io/upload_images/796164-5b982393d237fa2d.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)
會在測試類的包中自動生成測試類

package com.example.news;

import org.junit.Before;
import org.junit.Test;

import static org.junit.Assert.*;

/**

• Created by 小新 on 2016/7/1.
  */
  public class CalculatorTest {

  @Before
  public void setUp() throws Exception {

  }

  @Test
  public void testSum() throws Exception {

  }

  @Test
  public void testSubstract() throws Exception {

  }

  @Test
  public void testDivide() throws Exception {

  }

  @Test
  public void testMultiply() throws Exception {

  }

  @Test
  public void testAddMore() throws Exception {

  }
  }

然后進行測試

package com.example.news;

import org.junit.Before;
import org.junit.Test;

import static org.junit.Assert.*;

/**

• Created by 小新 on 2016/7/1.
  */
  public class CalculatorTest1 {
  private Calculator calculator;

  @Before
  public void setUp() throws Exception {
  calculator = new Calculator();

  }

  @Test
  public void testSum() throws Exception {
  //測試sum函數(shù)，因為sum函數(shù)返回的是兩個數(shù)的合為3
  //這里期望返回的值是9
  //所以會報錯
  assertEquals(9d,calculator.sum(1d,2d),0);
  }

  @Test
  public void testSubstract() throws Exception {

  }

  @Test
  public void testDivide() throws Exception {

  }

  @Test
  public void testMultiply() throws Exception {

  }

  @Test
  public void testAddMore() throws Exception {

  }
  }

運行這個類哥桥，結果為報錯，這個時候我們就需要修改函數(shù)了
到這里我們JUnix的簡單測試就結束了