add create_client tests

package.json

@@ -25,6 +25,7 @@
     "eslint-plugin-react": "~4.2.3",
     "expect.js": "~0.3.1",
     "mocha": "~2.4.5",
+    "proxyquire": "~1.7.4",
     "sinon": "~1.17.3"
   },
   "dependencies": {

src/index.js

@@ -5,6 +5,7 @@ import { omit } from 'lodash';
 export default class Elastique extends events.EventEmitter {
   constructor(options = {}) {
     if (!options.index) throw new Error('Must specify an index to write to');
+
     super();
 
     this.ready = true;

test/helpers/create_client.js

@@ -0,0 +1,28 @@
+import expect from 'expect.js';
+import proxyquire from 'proxyquire';
+
+const elasticsearchMock = {
+  Client: function Client() {}
+};
+
+const createClient = proxyquire.noPreserveCache()('../../lib/helpers/create_client', {
+  elasticsearch: elasticsearchMock
+});
+
+describe('Create client helper', function () {
+  it('should have a client', function () {
+    const options = {
+      host: 'http://localhost:9200'
+    };
+    const client = createClient(options);
+
+    expect(client).to.be.a(elasticsearchMock.Client);
+  });
+
+  it('should use passed in instance', function () {
+    const clientInstance = new elasticsearchMock.Client();
+    const client = createClient(clientInstance);
+
+    expect(client).to.equal(clientInstance);
+  });
+});