How to test Classes with @ConfigurationProperties and @Autowired

You need to annotate your TestConfiguration class with @EnableConfigurationProperties as follows:

@EnableConfigurationProperties
public class TestConfiguration {

    @Bean
    @ConfigurationProperties(prefix = "test")
    public TestSettings settings (){
        return new TestSettings();
    }
}

Also you only need to include TestConfiguration.class in @ContextConfiguration of your SettingsTest class:

@TestPropertySource(locations = "/SettingsTest.properties")
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = TestConfiguration.class)
public class SettingsTest {
...