Java单元测试中如何获取Vault值并注入类成员变量？

我有一个Java应用，通过依赖注入而非显式调用构造器的方式，将Vault中存储的值填充到类的成员变量中。生产环境的代码运行正常，但编写单元测试时遇到了问题。

生产环境正常运行的代码 #

MyVaultClass类 #

@Component
public class MyVaultClass {
    private final String vaultValue1;
    private final String vaultValue2;

    @Inject
    public MyVaultClass (@Value("${vaultValue1}") String vaultValue1, 
                         @Value("${vaultValue2}") String vaultValue2) {
        this.vaultValue1 = vaultValue1;
        this.vaultValue2 = vaultValue2;

        //Now the values are set
    }
}

MyService类 #

无需显式调用构造器，Spring会自动完成注入：

@Component
public class MyService {
    
    private final MyVaultClass myVaultClass ;

    @Inject
    public MyService (MyVaultClass myVaultClass ) {
        this.myVaultClass = myVaultClass;
    }
}

单元测试遇到的问题 #

尝试了两种测试方式均失败：

方式一：构造器注入失败 #

@RunWith(EasyMockRunner.class)
public class MyVaultClassTest {

    private MyVaultClass myVaultClass;

    //运行测试时失败
    @Inject
    public MyVaultClassTest (MyVaultClass myVaultClass) {
        this.myVaultClass = myVaultClass;
    }
}

方式二：Vault值为null #

@RunWith(EasyMockRunner.class)
public class MyVaultClassTest {

    @Mock
    private MyVaultClass myVaultClass;

    //运行不报错，但Vault值为null
    @Before
    public void setUp() {
        myVaultClass = new MyVaultClass(@Value("${vaultValue1}"), @Value("${vaultValue2}"));
    }
}

方案1：直接传入测试用硬编码值（单元测试首选） #

单元测试无需依赖Spring容器或Vault，直接手动构造MyVaultClass并传入测试固定值即可：

@RunWith(EasyMockRunner.class)
public class MyVaultClassTest {

    private MyVaultClass myVaultClass;

    @Before
    public void setUp() {
        // 直接传入模拟的Vault值，跳过@Value和Spring注入逻辑
        myVaultClass = new MyVaultClass("test-vault-value-1", "test-vault-value-2");
    }

    @Test
    public void testVaultValues() {
        // 需要给MyVaultClass添加getter方法访问私有变量
        assertEquals("test-vault-value-1", myVaultClass.getVaultValue1());
        assertEquals("test-vault-value-2", myVaultClass.getVaultValue2());
    }
}

提示：如果不想暴露getter，也可以测试依赖MyVaultClass的服务逻辑，间接验证值是否正确注入。

方案2：用Spring Test加载测试配置（集成测试场景） #

如果需要验证Spring的@Value注入逻辑，可启动Spring测试上下文，用测试属性替换真实Vault值：

@RunWith(SpringRunner.class)
@ContextConfiguration(classes = {MyVaultClass.class})
@TestPropertySource(properties = {
    "vaultValue1=test-value-1",
    "vaultValue2=test-value-2"
})
public class MyVaultClassTest {

    @Autowired
    private MyVaultClass myVaultClass;

    @Test
    public void testInjectedValues() {
        assertEquals("test-value-1", myVaultClass.getVaultValue1());
        assertEquals("test-value-2", myVaultClass.getVaultValue2());
    }
}

这种方式会初始化Spring容器，自动处理@Value注解，适合验证配置加载逻辑。

方案3：Mock依赖测试服务类 #

如果测试目标是MyService而非MyVaultClass，用EasyMock的@Mock和@InjectMocks自动注入模拟实例：

@RunWith(EasyMockRunner.class)
public class MyServiceTest {

    @Mock
    private MyVaultClass mockVaultClass;

    @InjectMocks
    private MyService myService;

    @Before
    public void setUp() {
        // 配置Mock的返回值
        EasyMock.expect(mockVaultClass.getVaultValue1()).andReturn("mock-value-1");
        EasyMock.expect(mockVaultClass.getVaultValue2()).andReturn("mock-value-2");
        EasyMock.replay(mockVaultClass);
    }

    @Test
    public void testServiceLogic() {
        // 测试MyService中依赖Vault值的业务逻辑
        String result = myService.doSomethingWithVaultValues();
        assertEquals("expected-result", result);
    }
}

内容的提问来源于stack exchange，提问作者Tim