How to write a test that expects an error to be issued in java

Question

I am testing this feature:

fun findByUsername(username: String): Account {
        return accountRepo.findByUsername(username).orElseThrow {
            UsernameNotFoundException("Username was not found")
        }
    }

here is my test

@Test
    fun checkFindByUsername() {
        val userRegistrationForm = UserRegistrationForm("testUser3", "123", "eee", false)
        val user = accountService.createAccount(userRegistrationForm)

        assertEquals(accountRepo.findByUsername("").orElseThrow {
            UsernameNotFoundException("Username was not found")
        }, "Username was not found")
    }

what to do to make the test pass? Do you need to use any specific assertion? sorry, understand that stupid question

when i ise assertThrows, appearts error: org.opentest4j.AssertionFailedError: Expected org.springframework.security.core.userdetails.UsernameNotFoundException to be thrown, but nothing was thrown. — wolfi, May 15 '20 at 01:53

score 2 · Accepted Answer · answered May 15 '20 at 01:28

2

Under the assumption that you're using JUnit (5), you can use Assertions.assertThrows.

Assertions.assertThrows(UsernameNotFoundException.class, () -> 
    accountRepo.findByUsername("")
);

answered May 15 '20 at 01:28

Marv

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when i ise assertThrows, appearts error: org.opentest4j.AssertionFailedError: Expected org.springframework.security.core.userdetails.UsernameNotFoundException to be thrown, but nothing was thrown. – wolfi May 15 '20 at 01:53
2

Then it seems like the Exception is no thrown... – Marv May 15 '20 at 01:55

score 0 · Answer 2 · answered May 15 '20 at 01:36

0

Use the expected parameter of the @Test annotation:

@Test(expected = UsernameNotFoundException.class)

answered May 15 '20 at 01:36

Bohemian

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I would recommend using `assertThrows` over this if JUnit 5 is available, because it specifies the exact point where the exception is expected and acceptable. – Marv May 15 '20 at 01:40

How to write a test that expects an error to be issued in java

2 Answers2