Which option is true about use of mocks in a Spring Boot web slice test? (Choose the best answer.)

Question

Options

• AMocking a Spring Bean requires annotating it with @MockBean annotation.
• BIf a Spring Bean already exists in the web slice test spring context, it cannot be mocked.
• CMocks cannot be used in a Spring Boot web slice test.
• DMocking a Spring Bean requires annotating it with @Mock annotation.

• A
  88% (21)
• C
  4% (1)
• D
  8% (2)

Explanation

Option A is correct because @MockBean is the Spring Boot-specific annotation that creates a Mockito mock and registers it in the Spring application context, replacing any existing bean of that type. In a @WebMvcTest (web slice test), collaborating beans like services aren't loaded, so @MockBean is the standard way to provide them to the context.

Why the distractors are wrong:

• B is the opposite of true - @MockBean can replace an existing bean in the Spring context with a mock, which is precisely its power.
• C is flatly false - mocking is not only allowed but expected in web slice tests, since the slice intentionally excludes most beans (e.g., services, repositories) that controllers depend on.
• D confuses @Mock (plain Mockito, no Spring integration) with @MockBean (Spring-aware mock). Using @Mock won't inject the mock into the Spring context, so the controller under test would receive a real or missing bean instead.

Memory tip: Think of the "B" in @MockBean as standing for "Bean" - it's the only annotation that puts the mock into the Spring Bean context. If you're in a Spring test, you need the Spring-aware version.

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