Implement bank http api

Use http4k library to implement http wrapper to the bank application.

This represent an adapter to the Bank interface, an implementation of
the driving port that defines the bank capabilities, and it trigger
actions on the application, the BankService.

Alongside the actual http application, create a client that can be used
externally to speak to the api, so that urls don't have to leak. Even
better, the client can implement the Bank contract so that tests are
implemented based on it.

Include 2 levels of testing, a simple in-memory test and an integration
test that spins up an http server.

As there's no intention to use a db or any other type of permanent
storage for this simple example, move the in-memory implementation of
the repository to production code so that it can be re-used.

Author: lmirabal

…nk/data/InMemoryBankAccountRepository.kt …nk/data/InMemoryBankAccountRepository.ktdomain/src/testFixtures/kotlin/lmirabal/bank/data/InMemoryBankAccountRepository.kt renamed to domain/src/main/kotlin/lmirabal/bank/data/InMemoryBankAccountRepository.kt domain/src/testFixtures/kotlin/lmirabal/bank/data/InMemoryBankAccountRepository.kt renamed to domain/src/main/kotlin/lmirabal/bank/data/InMemoryBankAccountRepository.kt

@@ -0,0 +1,8 @@
+dependencies {
+    implementation project(':domain')
+    implementation platform('org.http4k:http4k-bom:3.284.0')
+    implementation 'org.http4k:http4k-core'
+    implementation 'org.http4k:http4k-format-jackson'
+
+    testImplementation testFixtures(project(":domain"))
+}

http/build.gradle

@@ -0,0 +1,31 @@
+package lmirabal.bank.http
+
+import lmirabal.bank.Bank
+import lmirabal.bank.BankService
+import lmirabal.bank.data.InMemoryBankAccountRepository
+import lmirabal.bank.model.BankAccount
+import org.http4k.core.Body
+import org.http4k.core.HttpHandler
+import org.http4k.core.Method.GET
+import org.http4k.core.Method.POST
+import org.http4k.core.Response
+import org.http4k.core.Status.Companion.OK
+import org.http4k.core.with
+import org.http4k.format.Jackson.auto
+import org.http4k.routing.bind
+import org.http4k.routing.routes
+
+fun bankHttp() = bankHttp(BankService(InMemoryBankAccountRepository()))
+
+internal const val BANK_ACCOUNTS_URL = "/bank/accounts"
+internal val bankAccountLens = Body.auto<BankAccount>().toLens()
+internal val bankAccountListLens = Body.auto<List<BankAccount>>().toLens()
+
+internal fun bankHttp(bank: Bank): HttpHandler {
+    return routes(
+        BANK_ACCOUNTS_URL bind routes(
+            POST to { Response(OK).with(bankAccountLens of bank.createAccount()) },
+            GET to { Response(OK).with(bankAccountListLens of bank.listAccounts()) }
+        )
+    )
+}

http/src/main/kotlin/lmirabal/bank/http/BankHttp.kt

@@ -0,0 +1,20 @@
+package lmirabal.bank.http
+
+import lmirabal.bank.Bank
+import lmirabal.bank.model.BankAccount
+import org.http4k.core.HttpHandler
+import org.http4k.core.Method.GET
+import org.http4k.core.Method.POST
+import org.http4k.core.Request
+
+class BankHttpClient(val http: HttpHandler) : Bank {
+    override fun createAccount(): BankAccount {
+        val response = http(Request(POST, BANK_ACCOUNTS_URL))
+        return bankAccountLens(response)
+    }
+
+    override fun listAccounts(): List<BankAccount> {
+        val response = http(Request(GET, BANK_ACCOUNTS_URL))
+        return bankAccountListLens(response)
+    }
+}

http/src/main/kotlin/lmirabal/bank/http/BankHttpClient.kt

@@ -0,0 +1,28 @@
+package lmirabal.bank.http
+
+import lmirabal.bank.BankTest
+import org.http4k.client.JavaHttpClient
+import org.http4k.core.Uri
+import org.http4k.core.then
+import org.http4k.filter.ClientFilters.SetBaseUriFrom
+import org.http4k.server.SunHttp
+import org.http4k.server.asServer
+import org.junit.jupiter.api.AfterEach
+import org.junit.jupiter.api.BeforeEach
+
+class BankHttpIntegrationTest : BankTest() {
+    private val server = bankHttp().asServer(SunHttp())
+    override val bank = BankHttpClient(
+        SetBaseUriFrom(Uri.of("http://localhost:${server.port()}")).then(JavaHttpClient())
+    )
+
+    @BeforeEach
+    fun setUp() {
+        server.start()
+    }
+
+    @AfterEach
+    fun tearDown() {
+        server.stop()
+    }
+}

http/src/test/kotlin/lmirabal/bank/http/BankHttpIntegrationTest.kt

@@ -0,0 +1,7 @@
+package lmirabal.bank.http
+
+import lmirabal.bank.BankTest
+
+class BankHttpTest : BankTest() {
+    override val bank = BankHttpClient(bankHttp())
+}

http/src/test/kotlin/lmirabal/bank/http/BankHttpTest.kt

@@ -1,3 +1,4 @@
 rootProject.name = 'bank'
 
-include ':domain'
+include ':domain'
+include ':http'