Kotest Koin Extension

This page introduces the Kotest Koin extension.

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The Koin DI Framework can be used with Kotest through the KoinExtension extension.

To use the extension in your project, add the dependency to your project:

io.kotest.extensions:kotest-extensions-koin:${version}

Once the dependency is added, you can use Koin in tests easily.

class KotestAndKoin : FunSpec(), KoinTest {

    override fun extensions() = listOf(KoinExtension(myKoinModule))

    val userService by inject<UserService>()

    init {
        test("use userService") {
            userService.getUser().username shouldBe "LeoColman"
        }
    }
}

By default, the extension starts and stops the Koin context between leaf tests. If you use a nested spec style such as DescribeSpec and want to keep the Koin context across all leaves of a root test, for example to share mock declarations between tests, you can specify the lifecycle mode as KoinLifecycleMode.Root in the KoinExtension constructor.

class KotestAndKoin : DescribeSpec(), KoinTest {

    override fun extensions() = listOf(KoinExtension(module = myKoinModule, mode = KoinLifecycleMode.Root))

    val userService by inject<UserService>()

    init {
        describe("use userService") {
            it("inside a leaf test") {
                userService.getUser().username shouldBe "LeoColman"
            }
            it("this shares the same context") {
                userService.getUser().username shouldBe "LeoColman"
            }
        }
    }
}

References

Koin | Kotest