@RunWith(SpringRunner.class)

@SpringBootTest(classes = GetServerPortApplication.class,

  webEnvironment = SpringBootTest.WebEnvironment.DEFINED_PORT)

@ActiveProfiles("fixedport")

public class GetServerFixedPortUnitTest {

    private final static int EXPECTED_PORT = 7777;

    ....

}

@RunWith(SpringRunner.class) – This will join the JUnit test with the Spring TestContext

@SpringBootTest( … SpringBootTest.WebEnvironment.DEFINED_PORT) – In the SpringBootTest, we'll use the DEFINED_PORT for the embedded web server

@ActiveProfiles(“fixedport”) – With this annotation, we enabled the Spring profile “fixedport” so that our application-fixedport.properties will be loaded