Lint integration test files and browser test files (#1612)

* clean up utils

* more cleanup

* remove client.sign

* remove unneeded tests

* remove unneeded infra

* move helper functions to separate files

* fix linter issues

* more cleanup

* make helper functions more generally useful

* fix test account funding

* add import note to README

* lint browser tests

* run eslint --fix

test/integration/setup.ts

@@ -0,0 +1,36 @@
+import { generateXAddress, Client } from 'xrpl-local'
+
+import serverUrl from './serverUrl'
+import { ledgerAccept } from './utils'
+
+export async function teardownClient(this: Mocha.Context): Promise<void> {
+  this.client.disconnect()
+}
+
+export async function suiteClientSetup(this: Mocha.Context): Promise<void> {
+  this.transactions = []
+
+  await setupClient.bind(this)(serverUrl)
+  ledgerAccept(this.client)
+  this.newWallet = generateXAddress({ includeClassicAddress: true })
+  // two times to give time to server to send `ledgerClosed` event
+  // so getLedgerVersion will return right value
+  await ledgerAccept(this.client)
+  const response = await this.client.request({
+    command: 'ledger',
+    ledger_index: 'validated',
+  })
+  const ledgerVersion = response.result.ledger_index
+  this.startLedgerVersion = ledgerVersion
+  await teardownClient.bind(this)()
+}
+
+export async function setupClient(
+  this: Mocha.Context,
+  server = serverUrl,
+): Promise<void> {
+  return new Promise<void>((resolve, reject) => {
+    this.client = new Client(server)
+    this.client.connect().then(resolve).catch(reject)
+  })
+}