[Question] Testing with couroutine context

[moutyque]

Hello,

I wanted to use and test your wrapper inside a kotlin backend application.

I tried to test the ttl mechanisme with runTest and coroutine context but it failed:

    @Test
    fun `test test context to drop expired entry`() = runTest{

        val cache  =Caffeine
            .newBuilder()
            .expireAfterAccess(1.hours)
            .withEvictionListener { key, value, cause ->
                when (cause) {
                    RemovalCause.SIZE -> print("Removed $key due to size constraints")
                    RemovalCause.EXPIRED -> print("Removed $key due to time constraints")
                    RemovalCause.EXPLICIT -> print("Explicitly removed $key")
                    else -> ""
                }
            }.asCache<String, String>()

        cache.put("foo","bar")
        Assertions.assertThat(cache.getIfPresent("foo")).isEqualTo("bar")
        delay(2.hours)
        Assertions.assertThat(cache.getIfPresent("foo")).isNull() <-- return bar and not null
        
    }

I know I should inject my coroutine context somewhere to make it work and I saw the two parameters in Caffeine cache:

class Cache<K, V>(
   @Deprecated("This should be ignored - use overloaded methods") private val defaultScope: CoroutineScope,
   @Deprecated("This should be ignored - use overloaded methods") private val useCallingContext: Boolean,
   private val cache: AsyncCache<K, V>
)

How to inject coroutine context for testing ?
Is it even usefull as the underling lib is using completatble future ?

Thank you for any help / feedback and for this nice wrapper :)

[sksamuel]

You want to test using virtual time? That's what you're asking, so that the 1 hour test can complete immediately?
If so, you can't do that as Caffeine is responsible for evicting the entries and doesn't know anything about the test scheduler used by runTest.
The easiest thing to do here is to have your test use 1 second expiries and delay for 3 seconds or something.

[moutyque]

Hello, *you can't do that as Caffeine is responsible for evicting the entries and doesn't know anything about the test scheduler used by runTest* That is exactly my issue. When using a coroutine lib I am expecting to allows usage of tes scheduler but perhaps it is just me. Anyway I fall back to the classic lib. Cordialement Quentin Mouty ***@***.*** Le sam. 19 juil. 2025, 21:20, Sam ***@***.***> a écrit :

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*sksamuel* left a comment (sksamuel/aedile#43) <#43 (comment)> You want to test using virtual time? That's what you're asking, so that the 1 hour test can complete immediately? If so, you can't do that as Caffeine is responsible for evicting the entries and doesn't know anything about the test scheduler used by runTest. The easiest thing to do here is to have your test use 1 second expiries and delay for 3 seconds or something. — Reply to this email directly, view it on GitHub <#43 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AGCJDAL5G2NHG3D5YBV5TE33JKK65AVCNFSM6AAAAAB64KUCWCVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTAOJSGUZDKOBRGA> . You are receiving this because you authored the thread.Message ID: ***@***.***>