Injecting Spring Boot component with Mockito mocks

Injecting Spring Boot component with Mockito mocks

Not sure if this is a Spring Boot question or a Mockito question.

Not sure if this is a Spring Boot question or a Mockito question.

I have the following Spring Boot @Component class:

class StartupListener implements ApplicationListener<ContextRefreshedEvent>, KernelConstants {
    private Fizz fizz;

private Buzz buzz;

public void onApplicationEvent(ContextRefreshedEvent event) {
    // Do stuff involving 'fizz' and 'buzz'


So StartupListener has no constructor and is intentionally a Spring @Component that gets its properties injected via @Autowired.

The @Configuration class providing these dependencies is here, for good measure:

public class MyAppConfiguration {
    public Fizz fizz() {
        return new Fizz("OF COURSE");

public Buzz buzz() {
    return new Buzz(1, true, Foo.Bar);


I am now trying to write a JUnit unit test for StartupListener, and I have been using Mockito with great success. I would like to create a mock Fizz and Buzz instance and inject StartupListenerwith them, but I'm not sure how:

public class StartupListenerTest {
  private StartupListener startupListener;

@Mock private Fizz fizz;

@Mock price Buzz buzz;

@Test public void on_startup_should_do_something() { Mockito.when(fizz.calculateSomething()).thenReturn(43);

// Doesn't matter what I'm testing here, the point is I'd like 'fizz' and 'buzz' to be mockable mocks
// WITHOUT having to add setter methods to StartupListener and calling them from inside test code!

} }

Any ideas as to how I can accomplish this?

javascript testing spring

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