Testing reading list from yaml file into list object

I'm trying to load a list from application-test.yaml into the class, but it doesn't work.

This is how my application-test.yaml looks like:

category-merchandiser:
-
  username: test
  password: blas3cret
  roles:
    - test
    - admin

And this is my class:

@Configuration
@ConfigurationProperties(prefix = "category-merchandiser")
public class CategoryMerchandiserUsersConfig {

    private List<CategoryMerchandiser> users = new ArrayList<>();
    ** getters & setters **

    public static class CategoryMerchandiser {

        private String username;
        private String password;
        private List<String> roles = new ArrayList<>();

    ** getters & setters **

This is how i'm trying to test if the size of my list is 2:

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = CategoryMerchandiserUsersConfig.class)
public class CategoryMerchandiserUsersTest {

    @Autowired
    CategoryMerchandiserUsersConfig config;

    @Test
    public void shouldLoadApplicationYamlToClass() {
        assertThat(config.getUsers().size(), is(2));
    }
}

My console output tells me that the list is empty:

java.lang.AssertionError: 
Expected: is <2>
     but: was <0>
Expected :is <2>

Actual   :<0>

What am i doing wrong? Hope you guys can help me.