add AccountService

src/main/kotlin/ltd/lulz/service/AccountService.kt

@@ -0,0 +1,19 @@
+package ltd.lulz.service
+
+import io.github.oshai.kotlinlogging.KotlinLogging
+import ltd.lulz.model.AccountEntity
+import ltd.lulz.repository.AccountRepository
+import org.springframework.stereotype.Service
+import reactor.core.publisher.Mono
+
+private val log = KotlinLogging.logger {}
+
+@Service
+class AccountService(
+    private val accountRepository: AccountRepository,
+) {
+
+    fun create(entity: AccountEntity): Mono<AccountEntity> = accountRepository
+        .save(entity)
+        .doOnNext { log.debug { "account created with id: ${it.id}" } }
+}

src/test/kotlin/ltd/lulz/service/AccountServiceTest.kt

@@ -0,0 +1,53 @@
+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.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 entity = AccountEntity(name = name, amount = amount)
+
+        val capture = slot<AccountEntity>()
+        every { repository.save(capture(capture)) } answers { Mono.just(capture.captured.copy(id = uuid)) }
+
+        // when stepped
+        StepVerifier.create(service.create(entity))
+            .assertNext { result ->
+                assertThat(result.id).isEqualTo(uuid)
+                assertThat(result.name).isEqualTo(name)
+                assertThat(result.amount).isEqualTo(amount)
+            }
+            .verifyComplete()
+
+        verify { repository.save(any()) }
+    }
+}