add account not found exception

- update balance in AccountController with onErrorResume
- update AccountService
  - update getForUpdateById with switchIfEmpty
  - update getById with switchIfEmpty
- add AccountNotFoundException

src/test/kotlin/ltd/lulz/controller/AccountControllerTest.kt

@@ -4,6 +4,7 @@ import io.mockk.every
 import io.mockk.mockk
 import java.math.BigDecimal
 import java.util.UUID
+import ltd.lulz.exception.AccountNotFoundException
 import ltd.lulz.model.Account
 import ltd.lulz.model.AccountEntity
 import ltd.lulz.service.AccountService
@@ -117,7 +118,7 @@ class AccountControllerTest {
         @Test
         fun `account balance fail`() {
             // given
-            every { accountService.getById(any()) } returns Mono.empty()
+            every { accountService.getById(any()) } returns Mono.error(AccountNotFoundException())
 
             // when
             val result = webTestClient.get()

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

@@ -6,6 +6,7 @@ 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
@@ -70,6 +71,19 @@ class AccountServiceTest {
         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
@@ -89,6 +103,20 @@ class AccountServiceTest {
         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