Java 依赖注入单元测试

Question

有人可以对这个类进行junit测试吗？

public class MyApplication {
    private EmailService email = new EmailService();

    public boolean processMessages (String msg , String recipient ) {
        if (msg.length ==0 | | recipient.length ==0 ) {
            return false ;
        }
        return this.email.sendEmail (msg , recipient ) ;
    }
}

Answer 1

您的标题清楚地说明了问题：您没有注入对EmailService. 为此，请添加一个 setter 或（更好） make 并将其final添加到构造函数中。

那看起来像：

public class MyApplication {
    private final EmailService email;

    public MyApplication(EmailService email) {
        this.email = email;
    }

    public boolean processMessages (String msg , String recipient ) {
        if (msg.length == 0 || recipient.length == 0 ) {
            return false ;
        }
        return this.email.sendEmail (msg , recipient ) ;
    }
}

适当的测试可能是（使用 junit 和 mockito）：

private MyApplication app;
private EmailService email;

@BeforeEach
void setup() {
    email = mock(EmailService.class);
    when(email.sendEmail(any(), any())).thenReturn(true);
    app = new MyApplication(email);
}

@Test
void testProcessZeroLengthMessageOrPerson() {
    assertFalse(app.processMessages("", "Person"));
    assertFalse(app.processMessages("Message", "")):
    assertFalse(app.processMessages("", "")):
}

@Test
void testProcessMessage() {
    assertTrue(app.processMessage("Message", "Person"));
    verify(email).sendEmail("Message", "Person");
}