Improved controller to return 403 and error message instead of 500.

src/main/java/com/microsocialnetwork/users/controller/FriendsController.java

@@ -24,33 +24,33 @@ public class FriendsController {
 	private FriendsService friendsService;
 	
 	@PostMapping(value = "/request", headers = "Authorization")
-	public ResponseEntity<Boolean> request(@RequestParam String friendname, 
+	public ResponseEntity<String> request(@RequestParam String friendname, 
 			@AuthenticationPrincipal UserDetails signedUser) {
-		return new ResponseEntity<Boolean>(friendsService.request(friendname, signedUser), HttpStatus.OK);
+		return friendsService.request(friendname, signedUser);
 	}
 
 	@PostMapping(value = "/reject", headers = "Authorization")
-	public ResponseEntity<Boolean> reject(@RequestParam String friendname, 
+	public ResponseEntity<String> reject(@RequestParam String friendname, 
 			@AuthenticationPrincipal UserDetails signedUser) {
-		return new ResponseEntity<Boolean>(friendsService.reject(friendname, signedUser), HttpStatus.OK);
+		return friendsService.reject(friendname, signedUser);
 	}
 
 	@PostMapping(value = "/accept", headers = "Authorization")
-	public ResponseEntity<Boolean> accept(@RequestParam String friendname, 
+	public ResponseEntity<String> accept(@RequestParam String friendname, 
 			@AuthenticationPrincipal UserDetails signedUser) {
-		return new ResponseEntity<Boolean>(friendsService.accept(friendname, signedUser), HttpStatus.OK);
+		return friendsService.accept(friendname, signedUser);
 	}
 
 	@PostMapping(value = "/makeBest", headers = "Authorization")
-	public ResponseEntity<Boolean> makeBest(@RequestParam String friendname, 
+	public ResponseEntity<String> makeBest(@RequestParam String friendname, 
 			@AuthenticationPrincipal UserDetails signedUser) {
-		return new ResponseEntity<Boolean>(friendsService.makeBest(friendname, signedUser), HttpStatus.OK);
+		return friendsService.makeBest(friendname, signedUser);
 	}
 
 	@PostMapping(value = "/undoBest", headers = "Authorization")
-	public ResponseEntity<Boolean> undoBest(@RequestParam String friendname, 
+	public ResponseEntity<String> undoBest(@RequestParam String friendname, 
 			@AuthenticationPrincipal UserDetails signedUser) {
-		return new ResponseEntity<Boolean>(friendsService.undoBest(friendname, signedUser), HttpStatus.OK);
+		return friendsService.undoBest(friendname, signedUser);
 	}
 
 	@GetMapping(value = "/all", headers = "Authorization")

src/main/java/com/microsocialnetwork/users/controller/UserController.java

@@ -7,6 +7,8 @@ import javax.validation.Valid;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.support.DelegatingMessageSource;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
 import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
 import org.springframework.validation.BindingResult;
 import org.springframework.validation.annotation.Validated;
@@ -17,7 +19,6 @@ import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
 import com.microsocialnetwork.users.dto.SignupRequest;
-import com.microsocialnetwork.users.exceptions.MicroSocialNetworkException;
 import com.microsocialnetwork.users.model.User;
 import com.microsocialnetwork.users.repository.UserRepository;
 
@@ -33,18 +34,19 @@ public class UserController {
 
 	@PostMapping("/sign-up")
 	@Validated
-	public void signUp(@RequestBody @Valid SignupRequest request,
+	public ResponseEntity<String> signUp(@RequestBody @Valid SignupRequest request,
 			BindingResult bindingResult) {
 		if (bindingResult.hasErrors()) {
 			DelegatingMessageSource d = new DelegatingMessageSource();
 			String message = bindingResult.getAllErrors().stream()
 				.map(error -> d.getMessage(error, Locale.getDefault()))
 				.collect(Collectors.joining(", "));
-			throw new MicroSocialNetworkException(message);
+			return ResponseEntity.status(HttpStatus.FORBIDDEN).body(message);
 		}
 		User user = new User(request.getUsername(),	request.getEmail(),
 				bCryptPasswordEncoder.encode(request.getPassword()));
 		userRepository.save(user);
+		return new ResponseEntity<>("Signed up as " + request.getUsername(), HttpStatus.OK);
 	}
 
 	@GetMapping(headers = {"Authorization"})

src/main/java/com/microsocialnetwork/users/service/FriendsService.java

 package com.microsocialnetwork.users.service;
 
+import static org.springframework.test.web.client.match.MockRestRequestMatchers.content;
+
 import java.util.Arrays;
-import java.util.HashSet;
 import java.util.List;
-import java.util.Map;
 import java.util.Set;
 import java.util.function.Predicate;
 import java.util.stream.Collectors;
@@ -11,6 +11,8 @@ import java.util.stream.Collectors;
 import javax.transaction.Transactional;
 
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
 import org.springframework.security.core.userdetails.UserDetails;
 import org.springframework.stereotype.Service;
 
@@ -32,8 +34,11 @@ public class FriendsService {
 	private FriendLinkRepository linkRepository;
 
 	@Transactional
-	public Boolean request(String friendname, UserDetails signedUser) {
+	public ResponseEntity<String> request(String friendname, UserDetails signedUser) {
 		Context ctx = new Context(friendname, signedUser);
+		if (ctx.error != null) {
+			return ResponseEntity.status(HttpStatus.FORBIDDEN).body(ctx.error);
+		}
 		if (ctx.direct == null) {
 			// 1. There were no prior requests
 			ctx.createNewLink();
@@ -42,8 +47,9 @@ public class FriendsService {
 			// 2.  There was a rejection, try new request.
 			if (ctx.reverse.getRejectCount() >= 3) {
 				//However, if the target side rejected source repeatedly, deny.
-				throw new MicroSocialNetworkException("Request denied: You have bean rejected by "
-				  + friendname + " " + ctx.reverse.getRejectCount() + " times.");
+				String message = "Request denied: You have bean rejected by "
+						  + friendname + " " + ctx.reverse.getRejectCount() + " times.";
+				return ResponseEntity.status(HttpStatus.FORBIDDEN).body(message);
 			}
 			ctx.direct.setStatus(FriendStatusEnum.REQUEST_TO_THE_OTHER);
 			ctx.direct.setRejectCount(0);
@@ -53,48 +59,46 @@ public class FriendsService {
 			ctx.direct.onAccept();
 			ctx.reverse.onAccepted();
 		} else {
-			return false;
+			return ResponseEntity.status(HttpStatus.FORBIDDEN).body("You have already sent the request.");
 		}
 		ctx.save();
-		return true;
+		return ResponseEntity.status(HttpStatus.OK).body("Request is sent to " + friendname);
 	}
 
 	@Transactional
-	public Boolean reject(String friendname, UserDetails signedUser) {
+	public ResponseEntity<String> reject(String friendname, UserDetails signedUser) {
 		Context ctx = new Context(friendname, signedUser);
-		if (ctx.direct != null && (ctx.direct.getStatus().isFriend() || ctx.direct.getStatus() == FriendStatusEnum.REQUEST_BY_THE_OTHER)) {
+		if (ctx.error == null && ctx.direct != null && (ctx.direct.getStatus().isFriend() || ctx.direct.getStatus() == FriendStatusEnum.REQUEST_BY_THE_OTHER)) {
 			//If you are requested, you may reject the request;
 			//If you two are friends, you may reject the friendship.
 			ctx.direct.onReject();
 			ctx.reverse.onRejected();
 			ctx.save();
-			return true;
+			return ResponseEntity.status(HttpStatus.OK).body("You rejected friendship of " + friendname + ".");
 		} else {
-			//You cannot reject a person who is not your friend, nor requested you.
-			return false;
+			return ResponseEntity.status(HttpStatus.FORBIDDEN).body("You cannot reject a person who is not your friend, nor requested you.");
 		}
 	}
 
 	@Transactional
-	public Boolean accept(String friendname, UserDetails signedUser) {
+	public ResponseEntity<String> accept(String friendname, UserDetails signedUser) {
 		Context ctx = new Context(friendname, signedUser);
-		if (ctx.direct != null && (ctx.direct.getStatus() == FriendStatusEnum.REQUEST_BY_THE_OTHER)) {
+		if (ctx.error == null && ctx.direct != null && (ctx.direct.getStatus() == FriendStatusEnum.REQUEST_BY_THE_OTHER)) {
 			//If you are requested, you may reject the request;
 			//If you two are friends, you may reject the friendship.
 			ctx.direct.onAccept();
 			ctx.reverse.onAccepted();
 			ctx.save();
-			return true;
+			return ResponseEntity.status(HttpStatus.OK).body("You named " + friendname + " your friend!");
 		} else {
-			//You cannot reject a person who is not your friend, nor requested you.
-			return false;
+			return ResponseEntity.status(HttpStatus.FORBIDDEN).body(friendname + " did not request for your friennship, but may extends your request.");
 		}
 	}
 
 	@Transactional
-	public Boolean makeBest(String friendname, UserDetails signedUser) {
+	public ResponseEntity<String> makeBest(String friendname, UserDetails signedUser) {
 		Context ctx = new Context(friendname, signedUser);
-		if (ctx.direct != null && (ctx.direct.getStatus().isFriend() && !ctx.direct.getStatus().isBestFriend())) {
+		if (ctx.error == null && ctx.direct != null && (ctx.direct.getStatus().isFriend() && !ctx.direct.getStatus().isBestFriend())) {
 			if (ctx.reverse.getStatus().isBestFriend()) {
 				ctx.direct.setStatus(FriendStatusEnum.MUTUAL_BEST_FRIENDSHIP);
 				ctx.reverse.setStatus(FriendStatusEnum.MUTUAL_BEST_FRIENDSHIP);
@@ -103,17 +107,16 @@ public class FriendsService {
 				ctx.reverse.setStatus(FriendStatusEnum.BEST_FRIENDSHIP_BY_THE_OTHER);
 			}
 			ctx.save();
-			return true;
+			return ResponseEntity.status(HttpStatus.OK).body("You named " + friendname + " your best friend!");
 		} else {
-			//You must be a friend to choose him the best friend.
-			return false;
+			return ResponseEntity.status(HttpStatus.FORBIDDEN).body("You can only select the best friend of your friends.");
 		}
 	}
 
 	@Transactional
-	public Boolean undoBest(String friendname, UserDetails signedUser) {
+	public ResponseEntity<String> undoBest(String friendname, UserDetails signedUser) {
 		Context ctx = new Context(friendname, signedUser);
-		if (ctx.direct != null && (ctx.direct.getStatus().isBestFriend())) {
+		if (ctx.error == null && ctx.direct != null && (ctx.direct.getStatus().isBestFriend())) {
 			if (!ctx.reverse.getStatus().isBestFriend()) {
 				ctx.direct.setStatus(FriendStatusEnum.FRIENDSHIP);
 				ctx.reverse.setStatus(FriendStatusEnum.FRIENDSHIP);
@@ -122,10 +125,9 @@ public class FriendsService {
 				ctx.reverse.setStatus(FriendStatusEnum.BEST_FRIENDSHIP_TO_THE_OTHER);
 			}
 			ctx.save();
-			return true;
+			return ResponseEntity.status(HttpStatus.OK).body("You excluded " + friendname + " from your best friends. He is still your friend, though...");
 		} else {
-			//You did not set him a best friend.
-			return false;
+			return ResponseEntity.status(HttpStatus.FORBIDDEN).body(friendname + "was not your the best friend.");
 		}
 	}
 
@@ -168,16 +170,21 @@ public class FriendsService {
 
 
 	public class Context {
+		String error = null;
 		User source;
 		User target;
 		FriendLink direct;
 		FriendLink reverse;
 
 		Context(String friendname, UserDetails signedUser) {
-			source = userRepository.findByUsername(signedUser.getUsername()).get();
-			target = userRepository.findByUsername(friendname).orElseThrow(() -> new MicroSocialNetworkException("User " + friendname + " not found."));
-			direct = linkRepository.findByUserAndFriend(source, target).orElse(null);
-			reverse = linkRepository.findByUserAndFriend(target, source).orElse(null);
+			target = userRepository.findByUsername(friendname).orElse(null);
+			if (target == null) {
+				error = "User " + friendname + " not found.";
+			} else {
+				source = userRepository.findByUsername(signedUser.getUsername()).get();
+				direct = linkRepository.findByUserAndFriend(source, target).orElse(null);
+				reverse = linkRepository.findByUserAndFriend(target, source).orElse(null);
+			}
 		}
 		
 		void createNewLink() {

src/test/java/com/microsocialnetwork/users/SignUpTest.java

@@ -4,6 +4,7 @@ import static org.junit.Assert.assertTrue;
 
 import java.util.Base64;
 
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -29,7 +30,8 @@ public class SignUpTest {
 	@Autowired
 	WebApplicationContext webApplicationContext;
 
-	void init() {
+	@BeforeEach
+	public void init() {
 		if (mvc == null) {
 	        mvc = MockMvcBuilders.webAppContextSetup(webApplicationContext).build();
 		}
@@ -37,7 +39,6 @@ public class SignUpTest {
 	
 	@Test
 	public void signUp() throws Exception {
-		init();
 		String uri = "/users/sign-up";
 		MvcResult mvcResult = mvc.perform(
 			MockMvcRequestBuilders.post(uri)
@@ -46,28 +47,25 @@ public class SignUpTest {
 			.accept(MediaType.APPLICATION_JSON_VALUE)
 		).andExpect(MockMvcResultMatchers.status().isOk())
 		.andReturn();
+		assertTrue("Expected name of signed up user in the response body.", mvcResult.getResponse().getContentAsString().indexOf("user_1") >= 0);
 	}
 
 	@Test
 	public void signUpWithUnacceptedUserName() throws Exception {
-		init();
 		String uri = "/users/sign-up";
-		try {
-			mvc.perform(
-					MockMvcRequestBuilders.post(uri)
-					.content("{\"username\":\"user 2\",\"password\":\"p\",\"email\":\"user_2@best.com\"}")
-					.header("Content-Type", "application/json")
-					.accept(MediaType.APPLICATION_JSON_VALUE)
-			).andExpect(MockMvcResultMatchers.status().isInternalServerError());
-		} catch (NestedServletException e) {
-			assertTrue(e.getCause().getMessage().startsWith("Username must use only letters"));
-		}
+		MvcResult mvcResult = mvc.perform(
+			MockMvcRequestBuilders.post(uri)
+				.content("{\"username\":\"user 2\",\"password\":\"p\",\"email\":\"user_2@best.com\"}")
+				.header("Content-Type", "application/json")
+				.accept(MediaType.APPLICATION_JSON_VALUE)
+		).andExpect(MockMvcResultMatchers.status().isForbidden())
+		.andReturn();
+		assertTrue("Expected description of valid username.", mvcResult.getResponse().getContentAsString().indexOf("must use only letters") >= 0);
 	}
 
 	@Test
 	public void getUsers() throws Exception {
-		init();
-//		signUp();
+//		signUp(); //do not need it as database is not reset.
 		String uri = "/users";
 		String auth = Base64.getEncoder().encodeToString("user_1:p".getBytes());
 		MvcResult mvcResult = mvc.perform(
@@ -77,7 +75,6 @@ public class SignUpTest {
 			).andExpect(MockMvcResultMatchers.status().isOk())
 			.andReturn();
 		String body = mvcResult.getResponse().getContentAsString();
-		System.out.println(body);
 		assertTrue(body.indexOf("user_1@best.com") >= 0);
 	}