java - 测试组件类

Question

我有一个看起来像这样的类，它是我的应用程序中使用的组件

@Component
public class SecurityUtility {

    private final String SALT = "salt";

    Random random;


    public SecurityUtility(Random random) {
        this.random = random;
    }

    @Bean
    public BCryptPasswordEncoder passwordEncoder() {
        return new BCryptPasswordEncoder(12, new SecureRandom(SALT.getBytes()));
    }

    public String randomPassword() {
        String SALTCHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";

        StringBuilder stringBuilder = new StringBuilder();
        Random rnd = new Random();

         while (stringBuilder.length() < 18) {
            int index =   rnd.nextInt() * SALTCHARS.length();
            stringBuilder.append(SALTCHARS.charAt(index));
        }
        String randPass = stringBuilder.toString();

        return randPass;
    }
}

我能做些什么来测试这样一个类，我该如何去做，通常我一直在做单元测试但是这个类，不知道什么类型的测试或如何去做。预先感谢您的任何建议。单元测试或任何其他测试。

使用固定种子进行测试

@RunWith(SpringRunner.class)
@SpringBootTest
@ContextConfiguration(classes = SecurityUtility.class)
public class SecurityUtilityTest {

    @MockBean
    Random random;

    @Test
    public void createRandomPasswordSeed() {

          random = new Random(1 );

        String randomPassword = new SecurityUtility(random).randomPassword();

        Assert.assertEquals("seed = 1" , "83T81EOKK3ZZB259U5" , randomPassword );
    }

错误

org.junit.ComparisonFailure:种子 = 1预期:83T81EOKK3ZZB259U5实际:Z49G2RLF0HJNNWZQCP

Answer 1

what can I do for the randomPasswordTest, test if the class returns a random string ?

你必须消除随机性。

最好的方法是通过 依赖注入(inject) 传递 Random 类的实例。然后您可以为您的测试传递一个类型为 Random 的测试替身。

这个测试替身 可能是使用模拟框架创建的模拟。

另一方面，Java 的 Random 类是一个伪随机生成器。这意味着从修复种子开始，它将始终产生相同的数字序列。因此，您可以简单地创建一个 Random 实例，并将修复种子作为您的测试替身:

Random predictableValueProducer= new Random(1); 

您可以在另一个测试方法中使用不同的种子并检查更改后的输出以确保您的代码确实使用了传入的 Random 对象。

---

i don't know how to go about it, can you show how it should look like ?

被测代码

@Component
public class SecurityUtility {
    private final String SALT = "salt";
    private final Random random;

    // I prefer constructor injection...
    public SecurityUtility(@Inject Random random){
         this.random = random ;
    }
    @Bean
    public String randomPassword() {
        String SALTCHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
        StringBuilder salt = new StringBuilder();        
        while (salt.length() < 18) {
            int index = random.nextInt(SALTCHARS.length());
            salt.append(SALTCHARS.charAt(index));
        }
        return  salt.toString();
    }
}

测试

public class SecurityUtilityTest {

    @Test
    public void createsRandomPasswordWithSeed1() {
        // arrange
        Random randomWithFixSeed = new Random(1);

        // act
        String randomPassword = 
           new SecurityUtility(randomWithFixSeed).randomPassword();

        // assert
        assertEquals("seed = 1", "83T81EOKK3ZZB2S9U5", randomPassword);
    }

    @Test
    public void createsRandomPasswordWithSeed2() {
        Random randomWithFixSeed = new Random(2);

        String randomPassword = 
           new SecurityUtility(randomWithFixSeed).randomPassword();

        assertEquals("seed = 2", "EYUT8GG2HYCC95OIH2", randomPassword);
    }
}

---

for some reason they are not fixed

测试仍然失败，因为您没有完成被测代码中所需的更改。它仍然在 randomPassword() 中创建一个新的 Random 对象，而不是使用您引入的成员变量。

删除这一行:

    Random rnd = new Random();

并改变这个:

        //int index =   rnd.nextInt() * SALTCHARS.length();
        int index =   random.nextInt() * SALTCHARS.length();

还有你误用random.nextInt() 应该是

        int index =   random.nextInt(SALTCHARS.length());

正如我已经建议的那样。

I tried to use the annotation @inject it came from dozer library and did not work , what library does that annotation belong to [...] I tried to use @Autowire but it shows no bean of type random – valik

注释与测试问题无关。它们在您的应用程序运行时的初始化阶段发挥作用。