Add new billing accounts send customer change svc (#396)

https://eaflood.atlassian.net/browse/WATER-4092

We are working on migrating the change billing account address functionality from the legacy code to this project. A key part of this is being able to tell the [Charging Module API](https://github.com/DEFRA/sroc-charging-module-api) about the change!

We've [[Added a] new CHA create customer change presenter](#395) and a [[..] new CHA create customer change service](#394). We now add a new `SendCustomerChangeService` to our /billing-accounts to manage both including dealing with any errors in the process.

app/services/billing-accounts/send-customer-change.service.js

@@ -0,0 +1,45 @@
+'use strict'
+
+/**
+ * Sends customer changes to the Charging Module
+ * @module SendCustomerChangeService
+ */
+
+const CreateCustomerChangePresenter = require('../../presenters/charging-module/create-customer-change.presenter.js')
+const CreateCustomerChangeService = require('../charging-module/create-customer-change.service.js')
+const ExpandedError = require('../../errors/expanded.error.js')
+
+/**
+ * Generates the customer change request data from the model instances provided and sends it to the Charging Module
+ *
+ * When a change is made to a billing account in WRLS the Charging Module API needs to be told. It is responsible for
+ * generating the customer data feed to SOP which will be used when invoices are generated from the bill runs we also
+ * send it.
+ *
+ * This service handles taking the data forwarded from the UI, formatting it via a presenter into what the CHA expects
+ * and then sending the
+ * {@link https://defra.github.io/sroc-charging-module-api-docs/#/customer/CreateCustomerChange | POST request}.
+ *
+ * Should the request fail it will generate and throw an error.
+ *
+ * @param {module:InvoiceAccountModel} invoiceAccount The billing (invoice) account we are changing the address details
+ * for
+ * @param {module:AddressModel} address The new address
+ * @param {module:CompanyModel} company The agent company for the billing account if one was selected or setup by the
+ * user during the change address journey
+ * @param {module:ContactModel} contact The new contact for the billing account if an FAO was setup by the user during
+ * the change address journey
+ */
+async function go (invoiceAccount, address, company, contact) {
+  const requestData = CreateCustomerChangePresenter.go(invoiceAccount, address, company, contact)
+
+  const result = await CreateCustomerChangeService.go(requestData)
+
+  if (!result.succeeded) {
+    throw new ExpandedError('Customer change failed to send', { invoiceAccountId: invoiceAccount.invoiceAccountId })
+  }
+}
+
+module.exports = {
+  go
+}

test/services/billing-accounts/send-customer-change.service.test.js

@@ -0,0 +1,70 @@
+'use strict'
+
+// Test framework dependencies
+const Lab = require('@hapi/lab')
+const Code = require('@hapi/code')
+const Sinon = require('sinon')
+
+const { describe, it, beforeEach, afterEach } = exports.lab = Lab.script()
+const { expect } = Code
+
+// Test helpers
+const ExpandedError = require('../../../app/errors/expanded.error.js')
+
+// Things we need to stub
+const ChargingModuleCreateCustomerChangePresenter = require('../../../app/presenters/charging-module/create-customer-change.presenter.js')
+const ChargingModuleCreateCustomerChangeService = require('../../../app/services/charging-module/create-customer-change.service.js')
+
+// Thing under test
+const SendCustomerChangeService = require('../../../app/services/billing-accounts/send-customer-change.service.js')
+
+describe('Send billing transactions service', () => {
+  const invoiceAccount = { invoiceAccountId: '3b53f101-d256-40f8-a6be-ddefb5f9647c' }
+
+  beforeEach(() => {
+    Sinon.stub(ChargingModuleCreateCustomerChangePresenter, 'go').returns({
+      region: 'B',
+      customerReference: 'B19120000A',
+      customerName: 'Mr W Aston',
+      addressLine1: 'Park Farm',
+      addressLine2: 'Sugar Lane',
+      addressLine3: 'West Waterford',
+      addressLine4: 'Angleton',
+      addressLine5: 'Southampton',
+      addressLine6: 'Hampshire',
+      postcode: 'SO74 3KD'
+    })
+  })
+
+  afterEach(() => {
+    Sinon.restore()
+  })
+
+  describe('when calling the Charging Module API is successful', () => {
+    beforeEach(() => {
+      Sinon.stub(ChargingModuleCreateCustomerChangeService, 'go').resolves({
+        succeeded: true
+      })
+    })
+
+    it('does not throw an error', async () => {
+      await expect(SendCustomerChangeService.go(invoiceAccount)).not.to.reject()
+    })
+  })
+
+  describe('when calling the Charging Module API is unsuccessful', () => {
+    beforeEach(() => {
+      Sinon.stub(ChargingModuleCreateCustomerChangeService, 'go').resolves({
+        succeeded: false
+      })
+    })
+
+    it('throws an error', async () => {
+      const result = await expect(SendCustomerChangeService.go(invoiceAccount)).to.reject()
+
+      expect(result).to.be.an.instanceOf(ExpandedError)
+      expect(result.message).to.equal('Customer change failed to send')
+      expect(result.invoiceAccountId).to.equal(invoiceAccount.invoiceAccountId)
+    })
+  })
+})