A good test case

a-good-test-case.md

@Test
public void showProject_shouldReturnAccessDenied_forUnauthenticatedUser() {
    // Given an unauthenticated get project request
    HttpEntity request = unauthenticatedRequest("GET /projects/1");

    // When the request is handled by the application
    ResponseEntity<ErrorResponse> response = handleRequest(request);

    // Then a forbidden response should be returned
    assertThat(response).hasStatus(FORBIDDEN)
                        .isJson()
                        .hasMessage("Access Denied");
}

Now I call this a good JUnit test case:

1. It has no boilerplate code
2. It is small so it is possible to understand its intention quickly
3. It tests what it is supposed to test

It will become more concise if we declare variables using the var keyword:

@Test
public void showProject_shouldReturnAccessDenied_forUnauthenticatedUser() {
    // Given an unauthenticated get project request
    var request = unauthenticatedRequest("GET /projects/1");

    // When the request is handled by the application
    var response = handleRequest(request);

    // Then a forbidden response should be returned
    assertThat(response).hasStatus(FORBIDDEN)
                        .isJson()
                        .hasMessage("Access Denied");
}

And even more concise if we combine unauthenticatedRequest/handleRequest:

@Test
public void showProject_shouldReturnAccessDenied_forUnauthenticatedUser() {
    // Given an unauthenticated get project request
    var response = handleUnauthenticatedRequest("GET /projects/1");

    // Then a forbidden response should be returned
    assertThat(response).hasStatus(FORBIDDEN)
                        .isJson()
                        .hasMessage("Access Denied");
}