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[Spring Boot] Kotest + Mockk

by 민갤

Back End / Sep 01 2023

Kotest

Open source testing framework to test and validate kotlin code

It provides 10 test layouts to test various situations. (Link)

Mockk

Kotlin Mocking Framework

Write a test code based on Domain Specific Language (DSL).

Mocking: A simulated object. A test object that virtually replaces an external service or module.

Example

Tested services using Behavior Driven Development (BDD) method, BehaviorSpec

build.gradle.kts

testImplementation("io.kotest:kotest-runner-junit5:5.5.5")
testImplementation("io.kotest:kotest-assertions-core:5.5.5")
testImplementation("io.mockk:mockk:1.13.4")

Intellij Plugin Install

Settings → Plugins → Search 'Kotest' → Install

intellij_kotest.png

service (src>main>kotlin>package-path>service>UserServiceImpl)

@Service
class UserServiceImpl(
    private val userRepository: UserRepository
) : UserService {

    override fun login(email: String, password: String): String {
        // Account Inquiry
        val user = userRepository.findByEmail(email) ?: throw RuntimeException("email? $email")
        // Confirm password
        if (user.password != password) throw PasswordFailException()
        return getSession(email)
    }

    override fun getSession(email: String): String {
        return "session-key"
    }

}

test (src>test>kotlin>package-path>service>UserServiceTest)

internal class UserServiceTest : BehaviorSpec({
    // UserService dependency object declaration
    val userRepository = mockk<UserRepository>()
    // Test Data Declaration
    var email: String
    var password: String

    Given("Test Login") {
        email = "test@gmail.com"
        password = "test-password"

        // Inject dependency objects into UserService
        val service = withContext(Dispatchers.IO) {
            UserServiceImpl(userRepository)
        }

        When("If you enter a valid account") {
            // Set account lookup result value arbitrarily
            every { userRepository.findByEmail(any()) } returns user
            Then("Login Successful") {
                val result = service.login(email = email, password = password)
                // Verification of the result value
                result shouldNotBe null
                result shouldBe "session-key"
            }
        }

        When("If you enter an invalid account") {
            And("If you enter an email that does not exist") {
                every { userRepository.findByEmail(any()) } returns null

                Then("An exception occurs") {
                    val result = shouldThrow<RuntimeException> {
                        service.login(email = email, password = password)
                    }
                    result.message shouldBe "email? $email"
                }
            }
            And("If you enter the wrong password") {
                password = "test-password-1"
                every { userRepository.findByEmail(any()) } returns user

                Then("An exception occurs") {
                    shouldThrow<PasswordFailException> {
                        service.login(email = email, password = password)
                    }
                }
            }
        }
    }
}) {
    companion object {
        val user = User(
            id = 1L,
            email = "test@gmail.com",
            password = "test-password"
        )
    }
}