①在你的工程里导入JUnit4的包
②右击创建JUnit测试类，在测试类中编写测试代码即可。
JUnit 目前需要掌握的有一下几点：
Fixture系列：BeforeClass，AfterClass，Before，After
普通测试：Ignore（忽视），Text（测试），Test(timeout = 1000)（限时测试），Test(expected = ArithmeticException.class)（异常测试）
特殊测试：批量参数测试，打包测试
③Fixture系列与普通测试例代码
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1. package com.mikuscallion.main;
2.
3. import static org.junit.Assert.*;
4.
5. import org.junit.After;
6. import org.junit.AfterClass;
7. import org.junit.Before;
8. import org.junit.BeforeClass;
9. import org.junit.Ignore;
10. import org.junit.Test;
11. public class CalculatorTest {
12. //测试对象
13. Calculator calculator =new Calculator();
14. //Fixture
15. @BeforeClass
16. public static void beforeClass(){
17. System.out.println("在测试类初始化时，调用一次");
18. }
19. @AfterClass
20. public static void afterClass(){
21. System.out.println("在测试类运行结束时，调用一次");
22. }
23. @Before
24. public void before(){
25. System.out.println("执行任何测试代码前调用");
26. calculator.clear();
27. }
28. @After
29. public void after(){
30. System.out.println("执行任何测试代码后调用");
31. }
32. //Test---------------------------------------------------------------------------------
33. @Ignore
34. //忽视测试
35. public void testMultiply() {
36. calculator.multiply(1);
37. calculator.multiply(5);
38. //断言结果
39. assertEquals(5, calculator.getResult());
40. }
41. @Test(timeout = 1000)
42. //限时测试
43. public void limitTimeTest(){
44. calculator.squareRoot(5);
45. }
46. @Test(expected = ArithmeticException.class)
47. //异常测试
48. public void exceptTest(){
49. calculator.divide(0);
50. }
51. @Test
52. public void testAdd() {
53. calculator.add(1);
54. calculator.add(2);
55. assertEquals(3, calculator.getResult());
56. }
57. @Test
58. public void testSubstract() {
59. calculator.add(10);
60. calculator.substract(2);
61. assertEquals(8, calculator.getResult());
62. }
63. @Test
64. public void testDivide() {
65. calculator.add(8);
66. calculator.divide(2);
67. assertEquals(4, calculator.getResult());
68. }
69.
70. }
④参数测试代码
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1. package com.mikuscallion.main;
2.
3. import static org.junit.Assert.*;
4.
5. import java.util.Arrays;
6. import java.util.Collection;
7.
8. import org.junit.Test;
9. import org.junit.runner.RunWith;
10. import org.junit.runners.Parameterized;
11. import org.junit.runners.Parameterized.Parameters;
12.
13. @RunWith(Parameterized.class)
14. public class SquareTest {
15. public Calculator calculator =new Calculator();
16. public int param;
17. public int result;
18.
19. @Parameters
20. public static Collection data(){
21. //注意这种写法
22. return Arrays.asList(new Object[][]{
23. {2, 4},
24. {0, 0},
25. {-3, 9},
26. });
27. }
28. public SquareTest(int param, int result){
29. this.param = param;
30. this.result = result;
31. }
32. @Test
33. public void testSquare() {
34. calculator.square(param);
35. assertEquals(result, calculator.getResult());
36. }
37. }
⑤批量测试代码
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1. package com.mikuscallion.main;
2.
3.
4. import org.junit.runner.RunWith;
5. import org.junit.runners.Suite;
6. import org.junit.runners.Suite.SuiteClasses;
7. @SuiteClasses({
8. SquareTest.class,
9. CalculatorTest.class,
10. })
11. @RunWith(Suite.class)
12. public class SuiteTest {
13.
14. }
⑥被测试类代码
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1. package com.mikuscallion.main;
2. public class Calculator {
3.
4. private static int result; // 静态变量，用于存储运行结果
5.
6. public void add(int n){
7. result = result + n;
8. }
9. public void substract(int n){
10. result = result - n; //Bug: 正确的应该是 result =result-n
11. }
12. public void multiply(int n){
13. } // 此方法尚未写好
14. public void divide(int n){
15. result = result / n;
16. }
17.
18. //
19. public void square(int n){
20. result = n * n;
21. }
22. public void squareRoot(int n){
23. for (; ;) ; //Bug : 死循环
24. }
25. public void clear(){ // 将结果清零
26. result = 0;
27. }
28. public int getResult(){
29. return result;
30. }
31. }
github链接：https://github.com/SuNNed/Junit4/blob/master/test.md