Spring Boot Unit Tests with JWT Token Security

I believe that I solved the problem (and I hope I am not doing a bad practice or creating a security vulnerability on my backend).

I followed @punkrocker27ka’s advice and looked at this answer. In it they say that they are generating an Oauth token manually for the tests, so I decided to do the same thing for my JWT token.

So I updated my class that generates the JWT tokens and validates them to be like this:

public class TokenAuthenticationService {

    static final long EXPIRATIONTIME = 864_000_000; // 10 days
    static final String SECRET = "ThisIsASecret";
    static final String TOKEN_PREFIX = "Bearer";
    static final String HEADER_STRING = "Authorization";

    public static void addAuthentication(HttpServletResponse res, String username) {

        String jwt = createToken(username);

        res.addHeader(HEADER_STRING, TOKEN_PREFIX + " " + jwt);
    }

    public static Authentication getAuthentication(HttpServletRequest request) {
        String token = request.getHeader(HEADER_STRING);
        if (token != null) {
            // parse the token.
            String user = Jwts.parser()
                    .setSigningKey(SECRET)
                    .parseClaimsJws(token.replace(TOKEN_PREFIX, ""))
                    .getBody()
                    .getSubject();

            return user != null ?
                    new UsernamePasswordAuthenticationToken(user, null, Collections.emptyList()) :
                        null;
        }
        return null;
    }

    public static String createToken(String username) {
        String jwt = Jwts.builder()
                .setSubject(username)
                .setExpiration(new Date(System.currentTimeMillis() + EXPIRATIONTIME))
                .signWith(SignatureAlgorithm.HS512, SECRET)
                .compact();

        return jwt;
    }
}

And then I created a new test for it:

@RunWith(SpringRunner.class)
@SpringBootTest
@AutoConfigureMockMvc
public class TokenAuthenticationServiceTest {

    @Autowired
    private MockMvc mvc;

    @Test
    public void shouldNotAllowAccessToUnauthenticatedUsers() throws Exception {
        mvc.perform(MockMvcRequestBuilders.get("/test")).andExpect(status().isForbidden());
    }

    @Test
    public void shouldGenerateAuthToken() throws Exception {
        String token = TokenAuthenticationService.createToken("john");

        assertNotNull(token);
        mvc.perform(MockMvcRequestBuilders.get("/test").header("Authorization", token)).andExpect(status().isOk());
    }

}

Then I ran the tests and they passed, so the token was accepted without the need for the @WithMockUser annotation. I will add this to my other tests classes.

PS: The test endpoint is below.

/**
 * This controller is used only for testing purposes.
 * Especially to check if the JWT authentication is ok.
 */
@RestController
public class TestController {

    @RequestMapping(path = "/test", method = RequestMethod.GET)
    public String testEndpoint() {
        return "Hello World!";
    }
}