How to test deletion in JUnit (Play Framework)? - java

I need to make a JUnit test that checks whether it is possible to delete something from the database. I'm using the Play 2.1 Framework with an in-memory database.
I tried assertNull(...), but that failed. I then tried assertNotNUll(...) and the test passes, but I'm not sure this is the best way to do it or that it can even confirm deletion. Is there a better way to check if an item has been deleted? Should I look up the object and expect an error?
Here's my code (I also have some #BeforeClass and #AfterClass code, but it's no relevant to my question):
#Test
public void UserDelete(){
// Test ID: 3
// creating a new user
User user = new User();
user.id = (long) 4;
user.facebookId = "0000004";
user.email = "test4#gmail.com";
user.name = "name4";
user.save();
// deleting the user
user.delete();
// checking deletion
assertNotNull(user);
}

In general you usually have to do something like this. Of course this is a crude example but it points out that you should use some persistence solution like JPA to persist your domain objects.
#Test(expected = WhateverObjectNotFoundException.class)
public void removeUserTest(){
User u = UserFactory.createTestUser();
Long id = myEntityManager.persist(u);
assertNotNull(id);
myEntityManager.remove(u);
myEntityManager.findById(id);
}
In my opinion the User shouldn't be responsible for its lifecycle since it does not make sense to ask an object to delete itself hence your question is somewhat paradox.
This solution later can be generalized so you won't have to write it all over again when you test for the same kind of behavior.

You should insert new object in DB, check that is was inserted, delete it and check that it was deleted. Most obvious way is to use select count(*) to get number of rows.
public class ApplicationTest extends WithApplication {
#Before
public void setup() {
start(fakeApplication(inMemoryDatabase("default-test"), fakeGlobal()));
}
#Test
public void UserModify() {
// create user (User extends Model)
User user = new User();
user.setId(1);
user.setName("name1");
user.save();
int rowCount = Ebean.find(User.class).where().eq("id", 1).findRowCount();
assertEquals(1, rowCount);
user.delete();
rowCount = Ebean.find(User.class).where().eq("id", 1).findRowCount();
assertEquals(0, rowCount);
}
}

Related

JUnit test to delete an entity by id fails

I am trying to make a test for the method to delete an entity by id. I've written the test for the case when an entity with the given id doesn't exist, but in case when the entity exists, I'm apparently doing something wrong. This is the delete method from the service. I'm using the deleteById() method of the JpaRepository.
public void deleteById(Integer id) {
Optional<Agency> optionalAgency = repo.findAll().stream()
.filter(agency -> agency.getId().equals(id))
.findFirst();
if (optionalAgency.isPresent()) {
repo.deleteById(optionalAgency.get().getId());
} else {
throw new AgencyNotFoundException("Agency not found");
}
}
And this is my test:
#Mock
private AgencyRepository agencyRepository;
#Mock
private AgencyMapper mapper;
#InjectMocks
private AgencyService agencyService;
#Test
void delete() {
Agency agency = new Agency();
when(agencyRepository.findById(1)).thenReturn(Optional.of(agency));
agencyService.deleteById(1);
verify(agencyRepository).deleteById(1);
}
What assertion should I make in order to verify that the deletion was successful? The way I've tried it it doesn't work, the result of the test is that an exception is thrown. I'm guessing that the exception is thrown because agencyRepository.findById((int) 1L); basically doesn't exist anymore, but I thought maybe there's a better way to verify the deletion, without searching for the deleted object.
Not the answer, but your method could be written something like this:
public void deleteById(Integer id) {
Agency agency = repo.findById(id).orElseThrow(() -> throw new AgencyNotFoundException("Agency not found"));
repo.deleteById(agency.getId());
}
Because:
Optional<Agency> optionalAgency = repo.findAll().stream().filter(agency -> agency.getId().equals(id)).findFirst(); is not efficient. What if you have thousands of agencies? Will you fetch all and filter through all of them just to find by id. You have that method in your repository already.
if (optionalAgency.isPresent()) {} Optional.isPresent is not good practise. Read here and this answer
repo is a mock, so calling deleteById on it won't actually delete anything. Instead, you could verify that calling the AgencyService's deleteById actually calls AgencyRepository's deleteById.
EDIT:
The repository's code uses findAll, not findById, so you need to make sure you mock that:
#Test
void delete() {
Agency agency = new Agency();
agenct.setId((int) 1L);
when(agencyRepository.findAll()).thenReturn(Collections.singletonList(agency));
agencyService.deleteById((int) 1L);
verify(agencyRepository).delteById((int) 1L);
}

Data is autodeleted from in-memory database

I use HSQLDB for testing purpose. The problem is that when I add some data in init() method, then I can get that data only from the test which did run first.
#Before
public void init() {
if(isRun)
return;
isRun = true;
Role role = new Role();
role.setId(1);
role.setType("User");
roleDAO.save(role);
User user = new User();
user.setCredits(1000);
user.setEmail("User#test.com");
user.setUsername("User");
user.setPassword("qwerty");
user.setRoles(new HashSet<Role>(Arrays.asList(roleDAO.findById(1))));
userDAO.save(user);
User user2 = new User();
user2.setCredits(1000);
user2.setEmail("User2#test.com");
user2.setUsername("User2");
user2.setPassword("qwerty");
user2.setRoles(new HashSet<Role>(Arrays.asList(roleDAO.findById(1))));
userDAO.save(user2);
}
#Test
public void findUserByIdTest() {
User user = userDAO.findByUsername("User");
assertEquals(userDAO.findById(user.getId()), user);
}
#Test
public void addUserTest() {
User user = new User();
user.setCredits(1000);
user.setEmail("Antony#test.com");
user.setPassword("qwerty");
user.setUsername("Antony");
user.setRoles(new HashSet<Role>(Arrays.asList(roleDAO.findById(1))));
userDAO.save(user);
assertEquals(userDAO.findByUsername("Antony"), user);
}
#Test
public void updateUserTest() {
User user = userDAO.findByUsername("User");
user.setCredits(0);
assertEquals(userDAO.findByUsername("User").getCredits(), (Integer) 0);
}
#Test
public void removeUserTest() {
userDAO.remove(userDAO.findByUsername("User"));
assertNull(userDAO.findByUsername("User"));
}
So happens that removeUserTest() method always runs first and when I findAll() data then I see the data I set in init() method. After that, others test methods run but if I do findAll() there, it just returns nothing meaning no data exists.
In addition, I have set hibernate.hbm2ddl.auto=create.
What am I missing here? Why I can get data in the first running method but in others the data just disappears.
It's expected: Spring repository tests are transactional and the transaction is rollbacked at the end of each test by default.
Even if you choose not to rollback, every test should be independant from the others, and should be able to run alone. You should not rely on the execution order either. Your findUserByIdTest() would fail if removeUserTest() runs first.
So, start by cleaning the database and to insert the test data before each test. If you let Spring rollback after each test, cleaning is not necessary, but you should still insert the test data before each test.
Incrementing IDs should not be a problem: you just need to stire the created entities or their IDs in fields of the test, and refer to these entities and their IDs instead of using hard-coded IDs in the test.

Update/notify other User in Spring Web

I have some design/implementation issue that I just can't wrap my head around it. I am currently working on a text-based game with multiple players. I kind of understand how it works for Player-to-Server, I meant that Server sees every individual Player as the same.
I'm using spring-boot 2, spring-web, thymeleaf, hibernate.
I implemented a custom UserDetails that returns after the user login.
#Entity
#Table(name = "USER")
public class User implements Serializable {
#Id
private long userId;
#Column(unique = true, nullable = false)
private String userName;
#OneToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "playerStatsId")
private PlayerStats stats;
}
public class CurrentUserDetailsService implements UserDetailsService {
#Override
public CurrentUser loadUserByUsername(String userName) {
User user = this.accountRepository.findByUserName(userName)
.orElseThrow(() ->
new UsernameNotFoundException("User details not found with the provided username: " + userName));
return new CurrentUser(user);
}
}
public class CurrentUser implements UserDetails {
private static final long serialVersionUID = 1L;
private User user = new User();
public CurrentUser(User user) {
this.user = user;
}
public PlayerStats getPlayerStats() {
return this.user.getStats();
}
// removed the rest for brevity
}
Hence, in my controller, I can do this to get the CurrentUser.
*Note each User is also a player.
#GetMapping("/attackpage")
public String viewAttackPage(#AuthenticationPrincipal CurrentUser currentUser) {
// return the page view for list of attacks
return "someview";
}
The currentUser here would reflect to the current user per say (Player 1 or 2 or 3 and so on). Which works fine for most of the stuff happening to themselves such as purchasing some stuff, updating profile and so on.
But what I can't get or know how to achieve is when 2 players interact.
For example, Player 1 attacks Player 2. If I am Player 1, what I'll do is to click the "Attack" on the View and select the Player 2, and submit the command. Hence, in the controller, it will be something like this.
#GetMapping("/attack")
public String launchAttack(#AuthenticationPrincipal CurrentUser currentUser, #RequestParam("playername") String player2) {
updatePlayerState(player2);
return "someview";
}
public void updatePlayerState(String player) {
User user = getUserByPlayername(player);
// perform some update to player state (say health, etc)
// update back to db?
}
Here's is what really got me confused.
As seen previously, when each User/Player logs in, a set of user (player) current state will be pulled from the DB and store "in-memory".
Hence, when Player 1 attacks Player 2,
How do I "notify" or update Player 2 that the stats has changed, and thus, Player 2 should pull updated stats from db to memory.
How to tackle the possible concurrency issue here? For example, Player 2 health is 50 in DB. Player 2 then perform some action (say purchase health potion + 30), which then update the DB (health to 80). However, just before the DB is updated, Player 1 has already launch the attack and grab from DB the state of Player 2 where it will return 50 since DB has yet to be updated. So now, whatever changes made in getUserByPlayername() and update to the DB will be wrong, and the entire state of the Player will be "de-sync". I hope I am making sense here.
I understand that there is #Version in hibernate for optimistic locking but I'm not sure if it's applicable in this case. And would spring-session be useful in such case?
Should I not store the any data in memory when user login? Should I always be retrieving data from DB only when some action is performed? Like when viewProfile, then I pull from accountRepository. or when viewStats then I pull from statsRepository and on so.
Do point me in the right direction. Would appreciate for any concrete example of sort, or some kind of video/articles. If there is any additional information required, do let me know and I'll try to explain my case better.
Thank you.
I think that you should not be updating the currentUser in your Controller methods, and should not be relying on the data in that object to represent a player's current state. There are probably ways to get that to work, but you'd need to mess around with updating the security context.
I also recommend that you lookup Users by id instead of userName, so will write the rest of this answer with that approach. If you insist on finding Users by userName, adjust where necessary.
So, keeping it simple, I would have a reference to the accountRepository in the Controller, and then, whenever you need to get or update a player's state, use
User user = accountRepository.findById(currentUser.getId())
Yes, #Version and optimistic locking will help with the concurrency issues that you're concerned about. You can reload the Entity from the database, and retry the operation if you catch an #OptimisticLockException. Or, you may want to respond to player 1 with something like "Player 2 has just purchased a potion of healing, and is now 80 heath, do you still want to attack?"
I'm not a spring user, but I think that the problem is more conceptual than technical.
I'll try to provide an answer which uses a general approach, while writing the examples in a JavaEE style so that they should be understandable, and hopefully, portable to spring.
First of all: every single DETACHED entity is stale data. And stale data is not "trustable".
So:
each method that modify the state of an object should re-fetch the object from DB inside the transaction:
updatePlayerState() should be a transaction-boundary method (or called inside a tx), and getUserByPlayername(player) should fetch the target object from the DB.
JPA speaking: em.merge() is forbidden (without proper locking, i.e. #Version).
if you (or spring) are doing this already, there's little to add.
WRT the "lost update problem" you mention in your 2. be aware that this covers the application server side (JPA/Hibernate), but the very same problem could be present on DB side, which should be properly configured for, at least, repeatable read isolation. Take a look at MySQL does not conform to Repeatable Read really, if you are using it.
you have to handle controller fields that refer stale Players/Users/Objects. You have, at least, two options.
re-fetch for each request: suppose Player1 has attacked Player2 and diminished Player2 HP by 30. When Player2 goes to a view that shows his HP, the controller behind that view should have re-fetched the Player2/User2 entity before rendering the view.
In other words, all of your presentation (detached) entities should be, sort of, request-scoped.
i.e you can use a #WebListener to reload your Player/User:
#WebListener
public class CurrentUserListener implements ServletRequestListener {
#Override
public void requestInitialized(ServletRequestEvent sre) {
CurrentUser currentUser = getCurrentUser();
currentUser.reload();
}
#Override
public void requestDestroyed(ServletRequestEvent sre) {
// nothing to do
}
public CurrentUser getCurrentUser() {
// return the CurrentUser
}
}
or a request-scoped bean (or whatever-spring-equivalent):
#RequestScoped
public class RefresherBean {
#Inject
private CurrentUser currentUser;
#PostConstruct
public void init()
{
currentUser.reload();
}
}
notify other controller instances: if the update succeeded a notification should be sent to other controllers.
i.e. using CDI #Observe (if you have CDI available):
public class CurrentUser implements UserDetails {
private static final long serialVersionUID = 1L;
private User user = new User();
public CurrentUser(User user) {
this.user = user;
}
public PlayerStats getPlayerStats() {
return this.user.getStats();
}
public void onUpdate(#Observes(during = TransactionPhase.AFTER_SUCCESS) User user) {
if(this.user.getId() == user.getId()) {
this.user = user;
}
}
// removed the rest for brevity
}
Note that CurrentUser should be a server-managed object.

Why is this giving me AssertationError?

I have the following test :
#Test
public void deleteUser(){
User user = new User("admin","admin");
service.createUser(user);
service.deleteUser(1);
assertTrue("Check that user is deleted: ", user.getId() < 1);
}
But it gives me AssertationError.
Why can I not do like that?
I create my user and then wanna test that I am able to delete the newly created user.
My delete method is just deleting from a hashmap the user.
Map<Long, User> users = new HashMap<Long, User>();
protected static long nextId = 0;
#Override
public long createUser(User user) {
user.setId(getNextId());
users.put(user.getId(), user);
return user.getId();
}
#Override
public void deleteUser(long id) {
users.remove(id);
}
Can somebody explain this to me?
Instead of accessing the User object, that you still have the reference to (independent of whether it's deleted), you should implement a method, that checks, whether a user is present in the class of your service variable:
public boolean containsUser(long userId) {
return users.containsKey(userId);
}
And then assert like so:
assertFalse("Check that user is deleted: ", service.containsUser(1L));
When you delete user from Map, you do nothing with user.id. That's why your assertion fails.
One way to change id when deleting
#Override
public void deleteUser(long id) {
User deletedUser = users.remove(id);
deletedUser.setId(-1);
}
Another (and better) way is to change test:
#Test
public void deleteUser(){
User user = new User("admin","admin");
long id = service.createUser(user);
service.deleteUser(id);
assertFalse("Check that user is deleted: ", service.hasUser(id));
}
Your test does not make any sense - you want to check if the user is deleted from the service, but instead you are checking the value of the Id property of the user object (which is null, or set to some value - you did not provide any code). As some users already suggested, you need to check if the user is actually contained within your service. Also, are you doing something inside your getNextId() method? If that is simply getter for your nextId variable, every single user you create will have Id set to 0 (but maybe you wanted it that way, who knows). Is there some code within getNextId that actually sets the value to something else?

Why does my JUnit test (that modifies a database entry) fail

EDIT: replaced 'retrieve.name == "name1"' by 'retrieve.name.equals("name1")'.
EDIT2: Added #BeforeClass and #AfterClass (credit: http://digitalsanctum.com/2012/06/01/play-framework-2-tutorial-ebean-orm/).
I'm writing JUnit tests for a play web app and for some odd reason I can't seem to modify the database entries. Here's the simplest example I could come up with that illustrates the problem:
#BeforeClass
public static void setup() throws IOException {
app = Helpers.fakeApplication(Helpers.inMemoryDatabase());
Helpers.start(app);
server = Ebean.getServer("default");
ServerConfig config = new ServerConfig();
config.setDebugSql(true);
ddl = new DdlGenerator((SpiEbeanServer) server, new H2Platform(), config);
// drop
String dropScript = ddl.generateDropDdl();
ddl.runScript(false, dropScript);
// create
String createScript = ddl.generateCreateDdl();
ddl.runScript(false, createScript);
}
#AfterClass
public static void stopApp() {
// drop
String dropScript = ddl.generateDropDdl();
ddl.runScript(false, dropScript);
Helpers.stop(app);
}
#Test
public void UserModify(){
// create user (User extends Model)
User user = new User();
user.id = (long) 1;
user.name = "name1";
user.save();
// modify
user.name = "name2";
user.update();
user.save();
// look-up
User retrieve = User.find.byId((long) 1);
assertFalse("Old name", retrieve.name.equals("name1"));
}
Needless to say this should pass, but it doesn't... I know you can use "update()" to change database fields, because someone else on the project says he uses it like that and it works.
Play Framework documentation: http://www.playframework.com/documentation/2.1.1/Home
Any ideas why this test fails?
This is happening because of a problem in Play Framework.
Play doesn't enhance code in "test" folder, only in "app" folder.
Because of that getters and setters are not generated, and Ebean is relying on setters to detect that object is dirty and to support lazy loading. This way in your case Ebean doesn't know that property was updated on object.
As a simple solution, you can create getters and setters yourself. Also, that seems to be fixed already and probably should be included in next Play release: https://github.com/playframework/Play20/blob/master/framework/test/integrationtest-java/test/models/EbeanEnhancementTest.java
Here's a simple Play project with User model and working test: https://github.com/pharod/so-play2-issue1
See more details on getters and setters generation by Play here, in "Caveats" section near bottom of page: http://www.playframework.com/documentation/2.1.1/JavaEbean
As others have stated, you should use .equals() for string equality.
But the main problem is that to run this kind of tests (accessing the database) You need a running application.
In play, this could be done, by running a fake application with the test. Check out this guide:
http://www.playframework.com/documentation/2.0/JavaTest

Categories