feat(ledger): write audit_events row per ledger write

services/ledger/src/integrationTest/kotlin/com/fincore/ledger/application/AccountEntriesIT.kt

@@ -10,6 +10,7 @@ import com.fincore.core.AccountId
 import com.fincore.core.Currency
 import com.fincore.ledger.domain.enum.AccountType
 import com.fincore.ledger.domain.enum.EntryDirection
+import com.fincore.ledger.infrastructure.audit.AuditTrailWriterImpl
 import com.fincore.ledger.infrastructure.outbox.OutboxEventPublisherImpl
 import com.fincore.ledger.infrastructure.persistence.AccountPersistenceAdapter
 import com.fincore.ledger.infrastructure.persistence.TransactionPersistenceAdapter
@@ -41,6 +42,7 @@ import java.time.Instant
     AccountPersistenceAdapter::class,
     AccountEntriesIT.JacksonConfig::class,
     OutboxEventPublisherImpl::class,
+    AuditTrailWriterImpl::class,
 )
 class AccountEntriesIT(
     @Autowired private val entryQueryService: EntryQueryService,

services/ledger/src/integrationTest/kotlin/com/fincore/ledger/application/AccountIdempotencyServiceIT.kt

@@ -3,11 +3,15 @@
 
 package com.fincore.ledger.application
 
+import com.fasterxml.jackson.databind.ObjectMapper
+import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule
+import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
 import com.fincore.core.Currency
 import com.fincore.core.IdempotencyKey
 import com.fincore.ledger.domain.enum.AccountStatus
 import com.fincore.ledger.domain.enum.AccountType
 import com.fincore.ledger.domain.exception.IdempotencyConflictException
+import com.fincore.ledger.infrastructure.audit.AuditTrailWriterImpl
 import com.fincore.ledger.infrastructure.persistence.AccountBalanceEntity
 import com.fincore.ledger.infrastructure.persistence.AccountBalanceKey
 import com.fincore.ledger.infrastructure.persistence.AccountBalanceRepository
@@ -20,6 +24,8 @@ import org.junit.jupiter.api.extension.ExtendWith
 import org.springframework.beans.factory.annotation.Autowired
 import org.springframework.boot.test.autoconfigure.jdbc.AutoConfigureTestDatabase
 import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest
+import org.springframework.boot.test.context.TestConfiguration
+import org.springframework.context.annotation.Bean
 import org.springframework.context.annotation.Import
 import org.springframework.test.context.DynamicPropertyRegistry
 import org.springframework.test.context.DynamicPropertySource
@@ -34,12 +40,20 @@ import java.time.Instant
     AccountPersistenceAdapter::class,
     IdempotencyServiceImpl::class,
     IdempotencyStore::class,
+    AuditTrailWriterImpl::class,
+    AccountIdempotencyServiceIT.JacksonConfig::class,
 )
 class AccountIdempotencyServiceIT(
     @Autowired private val accountService: AccountService,
     @Autowired private val idempotencyService: IdempotencyService,
     @Autowired private val balanceRepository: AccountBalanceRepository,
 ) {
+    @TestConfiguration
+    class JacksonConfig {
+        @Bean
+        fun objectMapper(): ObjectMapper = jacksonObjectMapper().registerModule(JavaTimeModule())
+    }
+
     @Test
     fun `should create and read back an account`() {
         val created = accountService.create(CreateAccountCommand("Wallet", AccountType.USER_WALLET, Currency.USD, "auth0|op"))

services/ledger/src/integrationTest/kotlin/com/fincore/ledger/application/AuditRetryTopologyIT.kt

@@ -0,0 +1,119 @@
+// SPDX-License-Identifier: BUSL-1.1
+// SPDX-FileCopyrightText: 2026 FinCore Engine Authors
+
+package com.fincore.ledger.application
+
+import com.fasterxml.jackson.databind.ObjectMapper
+import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule
+import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
+import com.fincore.core.Currency
+import com.fincore.core.IdempotencyKey
+import com.fincore.ledger.domain.enum.AccountType
+import com.fincore.ledger.domain.enum.AuditAction
+import com.fincore.ledger.domain.enum.EntryDirection
+import com.fincore.ledger.infrastructure.audit.AuditTrailWriterImpl
+import com.fincore.ledger.infrastructure.outbox.OutboxEventPublisherImpl
+import com.fincore.ledger.infrastructure.persistence.AccountPersistenceAdapter
+import com.fincore.ledger.infrastructure.persistence.AuditEventRepository
+import com.fincore.ledger.infrastructure.persistence.TransactionPersistenceAdapter
+import com.fincore.ledger.infrastructure.persistence.TransactionRepository
+import com.fincore.test.containers.PostgresContainerExtension
+import io.kotest.matchers.shouldBe
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.extension.ExtendWith
+import org.springframework.beans.factory.annotation.Autowired
+import org.springframework.boot.test.autoconfigure.jdbc.AutoConfigureTestDatabase
+import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest
+import org.springframework.boot.test.context.TestConfiguration
+import org.springframework.context.annotation.Bean
+import org.springframework.context.annotation.Import
+import org.springframework.test.context.DynamicPropertyRegistry
+import org.springframework.test.context.DynamicPropertySource
+import java.math.BigDecimal
+
+/**
+ * Drives the real nesting idempotencyService.execute -> IdempotencyStore.runOrReplay (@Transactional)
+ * -> withOptimisticRetry -> TransactionPoster.post, and asserts that posting through that chain writes
+ * exactly one TRANSACTION_POST audit row together with the business write. The contended
+ * optimistic-retry-inside-the-idempotency-transaction path is a pre-existing concern tracked in a
+ * separate follow-up issue and is not exercised here.
+ */
+@DataJpaTest
+@AutoConfigureTestDatabase(replace = AutoConfigureTestDatabase.Replace.NONE)
+@ExtendWith(PostgresContainerExtension::class)
+@Import(
+    AccountServiceImpl::class,
+    AccountPersistenceAdapter::class,
+    TransactionServiceImpl::class,
+    TransactionPoster::class,
+    TransactionPersistenceAdapter::class,
+    BalanceServiceImpl::class,
+    IdempotencyServiceImpl::class,
+    IdempotencyStore::class,
+    AuditTrailWriterImpl::class,
+    OutboxEventPublisherImpl::class,
+    AuditRetryTopologyIT.JacksonConfig::class,
+)
+class AuditRetryTopologyIT(
+    @Autowired private val accountService: AccountService,
+    @Autowired private val transactionService: TransactionService,
+    @Autowired private val idempotencyService: IdempotencyService,
+    @Autowired private val auditRepository: AuditEventRepository,
+    @Autowired private val transactionRepository: TransactionRepository,
+) {
+    @TestConfiguration
+    class JacksonConfig {
+        @Bean
+        fun objectMapper(): ObjectMapper = jacksonObjectMapper().registerModule(JavaTimeModule())
+    }
+
+    private fun newAccount(): com.fincore.ledger.domain.Account =
+        accountService.create(CreateAccountCommand("Topology Account", AccountType.USER_WALLET, Currency.USD, ACTOR))
+
+    @Test
+    fun `should write exactly one TRANSACTION_POST audit row when post runs through the idempotency path`() {
+        val debit = newAccount()
+        val credit = newAccount()
+        val key = IdempotencyKey.of("retry-topo-happy-00000000000000000000000".take(40))
+        val body = """{"reference":"ref-topo-happy","currency":"USD"}"""
+        var postedId = ""
+
+        idempotencyService.execute(key, body) { hash ->
+            val posted =
+                transactionService.post(
+                    PostTransactionCommand(
+                        reference = "ref-topo-happy",
+                        description = null,
+                        currency = Currency.USD,
+                        entries =
+                            listOf(
+                                EntryLine(debit.id, EntryDirection.DEBIT, BigDecimal("100.00")),
+                                EntryLine(credit.id, EntryDirection.CREDIT, BigDecimal("-100.00")),
+                            ),
+                        actor = ACTOR,
+                        correlationId = CORR_ID,
+                        requestHash = hash,
+                    ),
+                )
+            postedId = posted.id.toString()
+            StoredResponse(201, """{"id":"${posted.id}"}""")
+        }
+
+        auditRepository.findAll().filter { it.resourceId == postedId && it.action == AuditAction.TRANSACTION_POST.name }.size shouldBe 1
+        transactionRepository.findAll().filter { it.reference == "ref-topo-happy" }.size shouldBe 1
+    }
+
+    companion object {
+        const val ACTOR = "auth0|topology-actor"
+        const val CORR_ID = "corr-retry-topo-001"
+
+        @JvmStatic
+        @DynamicPropertySource
+        fun datasourceProperties(registry: DynamicPropertyRegistry) {
+            registry.add("spring.datasource.url") { PostgresContainerExtension.jdbcUrl }
+            registry.add("spring.datasource.username") { PostgresContainerExtension.username }
+            registry.add("spring.datasource.password") { PostgresContainerExtension.password }
+            registry.add("spring.jpa.hibernate.ddl-auto") { "none" }
+        }
+    }
+}