basic-banking/src/test/kotlin/ltd/lulz/service/AccountServiceTest.kt

package ltd.lulz.service

import io.mockk.every
import io.mockk.mockk
import io.mockk.slot
import io.mockk.verify
import java.math.BigDecimal
import java.util.UUID
import ltd.lulz.exception.AccountNotFoundException
import ltd.lulz.model.AccountEntity
import ltd.lulz.repository.AccountRepository
import org.assertj.core.api.Assertions.assertThat
import org.junit.jupiter.api.BeforeEach
import org.junit.jupiter.api.Test
import reactor.core.publisher.Mono
import reactor.test.StepVerifier

@Suppress("ReactiveStreamsUnusedPublisher", "MayBeConstant")
class AccountServiceTest {

    companion object {
        val name: String = "some name"
        val amount: BigDecimal = BigDecimal.valueOf(0.01)
        val uuid: UUID = UUID.fromString("00000000-0000-0000-0000-000000000000")
    }

    private var repository: AccountRepository = mockk()
    private lateinit var service: AccountService

    @BeforeEach
    fun setUp() {
        service = AccountService(repository)
    }

    @Test
    fun `create account`() {
        // given
        val capture = slot<AccountEntity>()
        every { repository.save(capture(capture)) } answers { Mono.just(capture.captured.copy(id = uuid)) }

        // when stepped
        StepVerifier.create(service.create(name, amount))
            .assertNext { result ->
                assertThat(result.id).isEqualTo(uuid)
                assertThat(result.name).isEqualTo(name)
                assertThat(result.amount).isEqualTo(amount)
            }
            .verifyComplete()

        verify { repository.save(any()) }
    }

    @Test
    fun `get by id`() {
        // given
        val capture = slot<UUID>()
        every { repository.findById(capture(capture)) }
            .answers { Mono.just(AccountEntity(capture.captured, name, amount)) }

        // when stepped
        StepVerifier.create(service.getById(uuid))
            .assertNext { result ->
                assertThat(result.id).isEqualTo(uuid)
                assertThat(result.name).isEqualTo(name)
                assertThat(result.amount).isEqualTo(amount)
            }
            .verifyComplete()

        verify { repository.findById(any(UUID::class)) }
    }

    @Test
    fun `get by id - fail`() {
        // given
        every { repository.findById(any(UUID::class)) } returns Mono.empty()

        // when stepped
        StepVerifier.create(service.getById(uuid))
            .expectError(AccountNotFoundException::class.java)
            .verify()

        verify { repository.findById(any(UUID::class)) }
    }

    @Test
    fun `get for update by id`() {
        // given
        val capture = slot<UUID>()
        every { repository.findByIdForUpdate(capture(capture)) }
            .answers { Mono.just(AccountEntity(capture.captured, name, amount)) }

        // when stepped
        StepVerifier.create(service.getForUpdateById(uuid))
            .assertNext { result ->
                assertThat(result.id).isEqualTo(uuid)
                assertThat(result.name).isEqualTo(name)
                assertThat(result.amount).isEqualTo(amount)
            }
            .verifyComplete()

        verify { repository.findByIdForUpdate(any(UUID::class)) }
    }

    @Test
    fun `get for update by id - fail`() {
        // given

        every { repository.findByIdForUpdate(any(UUID::class)) } returns Mono.empty()

        // when stepped
        StepVerifier.create(service.getForUpdateById(uuid))
            .expectError(AccountNotFoundException::class.java)
            .verify()

        verify { repository.findByIdForUpdate(any(UUID::class)) }
    }

    @Test
    fun `save change`() {
        // given
        val entity = AccountEntity(name = name, amount = amount)

        val capture = slot<AccountEntity>()
        every { repository.save(capture(capture)) }
            .answers { Mono.just(capture.captured) }

        // when stepped
        StepVerifier.create(service.save(entity))
            .assertNext { result ->
                assertThat(result).isEqualTo(entity)
            }
            .verifyComplete()

        verify { repository.save(any()) }
    }
}