fix some eslint error

.eslintrc.json

@@ -5,7 +5,8 @@
   ],
   "parser": "babel-eslint",
   "env": {
-    "browser": true
+    "browser": true,
+    "mocha": true
   },
   "rules": {
     "import/no-extraneous-dependencies": "off",

tests/Carousel.spec.jsx

@@ -0,0 +1,53 @@
+import expect from 'expect.js';
+import React from 'react';
+import Enzyme, { mount } from 'enzyme';
+import Adapter from 'enzyme-adapter-react-15';
+import Carousel from '../src';
+
+Enzyme.configure({ adapter: new Adapter() });
+
+describe('Carousel', () => {
+  it('className prop works', () => {
+    const node = mount(<Carousel className="test-classname" />);
+    expect(node.props().className).to.equal('test-classname');
+  });
+
+  it('prefixCls prop works', () => {
+    const node = mount(<Carousel prefixCls="test-prefix" />);
+    expect(node.find('.test-prefix')).to.have.length(1);
+  });
+
+  it('centerDots prop works', () => {
+    const node1 = mount(<Carousel prefixCls="test-prefix" />);
+    expect(node1.find('.test-prefix-dots-centered')).to.have.length(1);
+
+    const node2 = mount(<Carousel prefixCls="test-prefix" centerDots={false} />);
+    expect(node2.find('.test-prefix-dots-centered')).to.have.length(0);
+  });
+
+  it('largeArrowsAndDots prop works', () => {
+    const node1 = mount(<Carousel prefixCls="test-prefix" />);
+    expect(node1.find('.test-prefix-large-mode')).to.have.length(0);
+
+    const node2 = mount(<Carousel prefixCls="test-prefix" largeArrowsAndDots />);
+    expect(node2.find('.test-prefix-large-mode')).to.have.length(1);
+  });
+
+  it('arrows === always works', () => {
+    const node1 = mount(<Carousel prefixCls="test-prefix" arrows="test" />);
+    expect(node1.find('.test-prefix-always-show-arrows')).to.have.length(0);
+
+    const node2 = mount(<Carousel prefixCls="test-prefix" arrows="always" />);
+    expect(node1.find('.test-prefix-always-show-arrows')).to.have.length(0);
+  });
+
+  it('coverage improve', () => {
+    mount(
+      <Carousel>
+        <div>
+          a
+        </div>
+      </Carousel>,
+    );
+  });
+});

tests/index.js

@@ -2,5 +2,5 @@
  * only require other specs here
  */
 
- const req = require.context('.', false, /\.spec\.js$/);
- req.keys().forEach(req);
+const req = require.context('.', false, /\.spec\.js(x)?$/);
+req.keys().forEach(req);