Como faço o teste do site A / B?
If I change the CSS, as soon as I reload the page (in the Network tab) it reloads the original CSS - obviously.
Você precisa realizar seu teste A / B de uma maneira diferente.
Abaixo estão algumas recomendações.
O melhor guia para testes A / B
Create Your First A/B Test
Once you’ve decided what to test, the next step, of course, is to select a tool for the job. If you want a free basic tool and don’t mind fiddling with HTML and JavaScript, go with Google Website Optimizer.
If you want an easier alternative with extra features, go with Visual Website Optimizer (disclaimer: my start-up).
Other options are available, which I discuss at the end of this post. Setting up the core test is more or less similar for all tools, so we can discuss it while remaining tool-agnostic.
You can set up an A/B test in one of two ways:
Replace the element to be tested before the page loads
If you are testing a single element on a Web page—say, the sign-up button—then you’ll need to create variations of that button (in HTML) in your testing tool.
When the test is live, the A/B tool will randomly replace the original button on the page with one of the variations before displaying the page to the visitor.
Redirect to another page
If you want to A/B test an entire page—say, a green theme vs. a red theme—then you’ll need to create and upload a new page on your website.
For example, if your home page is http://www.example.com/index.html, then you’ll need to create a variation located at http://www.example.com/index1.html. When the test runs, your tool will redirect some visitors to one of your alternate URLs.
Fonte O melhor guia para testes A / B