Inconsistent auto-decoding with spring #RequestParam - spring-mvc

Question

I have a normal spring #Controller which takes an URL-encoded string as parameter:
#RequestMapping(value = "/wechat/browser", method = GET)
public void askWeChatWhoTheUserIs(#RequestParam(name = "origin") String origin,
HttpServletResponse response) throws IOException {
//omitted codes
}
When I debug the spring boot application and test the endpoint with browser:
curl http://localhost:8080/wechat/browser\?origin\=http%3A%2F%2Fwww.example.com%2Findex.html%3Fa%3Db%23%2Froute
The origin got decoded automatically and equal to http://www.example.com/index.html?a=b#/route
But when I wrote a spring mvc test:
#RunWith(SpringRunner.class)
#WebMvcTest(WeChatOauthController.class)
public class WeChatOauthControllerTest {
#Autowired
private MockMvc mvc;
#Test
public void itShouldRedirectToWeChatToFinishOauthProtocol() throws Exception {
String origin = "http://www.example.com/index.html?a=b#/route";
String encodedOrigin = URLEncoder.encode(origin, "UTF-8");
this.mvc.perform(get("/wechat/browser")
.param("origin", encodedOrigin))
.andDo(print())
//omitted codes
}
}
When I debug this test and the controller, the origin was not decoded this time. Just wondering why it behaves differently in these two cases.

Answer 1

When supplying a request parameter with the Spring MVC Test framework, there is no need to manually encode the parameter's value since there is no physical HTTP request.
So, just use the original raw value in your test, and it should work fine.
In other words, use this:
#RunWith(SpringRunner.class)
#WebMvcTest(WeChatOauthController.class)
public class WeChatOauthControllerTest {
#Autowired
private MockMvc mvc;
#Test
public void itShouldRedirectToWeChatToFinishOauthProtocol() throws Exception {
this.mvc.perform(get("/wechat/browser")
.param("origin", "http://www.example.com/index.html?a=b#/route"))
.andDo(print())
//omitted codes
}
}

Answer 2

You can use this method , thus there will be proper decoding
#RunWith(SpringRunner.class)
#SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
public class WeChatOauthControllerTest {
#LocalServerPort
private int port;
TestRestTemplate restTemplate = new TestRestTemplate();
#Test
public void testAmpersandEncoded(){
ResponseEntity<String> response =
restTemplate.exchange(createURI("%26"),HttpMethod.GET, null, String.class);
assertEquals(response.getStatusCode(), HttpStatus.OK);
}
private URI createURI(String param){
URI uri = null;
String url = "http://localhost:"+ port +"/location?query=" + param;
try {
uri = new URI(url);
} catch (URISyntaxException e) {
log.error(e.getMessage());
}
return uri;
}