Error running JUnitWeb Test on Method setup

I have a Spring application, and I've created this test:

@RunWith(SpringRunner.class)
@SpringJUnitWebConfig(locations = {
        "classpath:testDatabaseContext.xml",
        "classpath:testServicesContext.xml",
        "classpath:backoffice-servlet.xml"
})
public class UserControllerTests {

    @Autowired
    private MockMvc mockMvc;

    @Before
    void setup(WebApplicationContext wac) {
        this.mockMvc = MockMvcBuilders.webAppContextSetup(wac).build();
    }
..
}

but when I start the test I got this error:

rg.junit.runners.model.InvalidTestClassError: Invalid test class 'com.pastis.UserControllerTests':
  1. Method setup() should be public
  2. Method setup should have no parameters

Here an example:

RunWith(SpringJUnit4ClassRunner.class)
@WebAppConfiguration
@ContextConfiguration(classes = MyWebConfig.class)
public class CustomerControllerTest {

    @Autowired
    private WebApplicationContext wac;

    private MockMvc mockMvc;

    @Before
    public void setup () {
        DefaultMockMvcBuilder builder = MockMvcBuilders.webAppContextSetup(this.wac);
        this.mockMvc = builder.build();
    }

    @Test
    public void testUserController () throws Exception {
        ResultMatcher ok = MockMvcResultMatchers.status()
                                                .isOk();

        MockHttpServletRequestBuilder builder = MockMvcRequestBuilders.get("/customers");
        this.mockMvc.perform(builder)
                    .andExpect(ok);

    }
}