test confusion 
it says multiple types,
but it's only one type

```js
  describe('given multiple types', function(){
    it('should return the first match or false', function(){
      var ctx = context();
      ctx.header['content-type'] = 'image/png';
      ctx.header['transfer-encoding'] = 'chunked';

      ctx.is('png').should.equal('png');
      ctx.is('.png').should.equal('.png');
      ctx.is('text/*', 'image/*').should.equal('image/png');
      ctx.is('image/*', 'text/*').should.equal('image/png');
      ctx.is('image/*', 'image/png').should.equal('image/png');
      ctx.is('image/png', 'image/*').should.equal('image/png');

      ctx.is(['text/*', 'image/*']).should.equal('image/png');
      ctx.is(['image/*', 'text/*']).should.equal('image/png');
      ctx.is(['image/*', 'image/png']).should.equal('image/png');
      ctx.is(['image/png', 'image/*']).should.equal('image/png');

      ctx.is('jpeg').should.be.false;
      ctx.is('.jpeg').should.be.false;
      ctx.is('text/*', 'application/*').should.be.false;
      ctx.is('text/html', 'text/plain', 'application/json; charset=utf-8').should.be.false;
    })
  })

```