SerenityBDD for clean Rest API tests

Serenity BDD helps you write cleaner and more maintainable automated acceptance and regression tests faster. As his name suggests, it is a tool for BDD, but in this post, I am going to show you that can be used standalone (no Cucumber or JBehave specs) just JUnit for testing Rest APIs.

Serenity BDD also implements the screenplay pattern, which encourages good testing habits and improves the readability of the tests.

Although Serenity BDD was created first with built-in support for web testing with Selenium 2, currently it also supports Rest API testing by using Rest-Assured out-of-the-box.

So let's see how to write some tests using Serenity BDD for Rest API services. For this example, we are going to use ReqRes service which provides a simple Rest service with fake data, so you don't need to create a demo service anymore, just use one. We are going to create some integration test for this service which we can call it User Service.

At the end of the post, you'll be able to get the source code of the example, but for now, let's see the important bits.

In @Before section, we are just setting the URL of the service under test. In this case, the URL is set by using a system property called restapi.baseurl, but of course there are other ways to do that like using serenity.conf or serenity.properties files.
Then you also define the actor. This has the responsibility of doing the action, in this case, we named Security Service because in our example we suppose that the Security Service is the consumer and the User Service (implemented by ReqRes) is the provider.

Then we are defining two tests, and notice how is the actor who is responsible for doing the actions. attemptsTo (for doing the request), and should (for asserting the response). As you can see every test now it is really readable on what is the purpose. Check for example the find_an_individual_user() test method. You can read almost as natural language something like "security service attempts to find a user with id 1 and it should see that the response is (...)".

And if you are curious, the FindAUser class looks like;

You only take performAs method to implement the logic to do the request (in this case a Get method). Similar is done with other Http methods.

So you can see that it is not mandatory to use BDD approach for using Serenity BDD, you can use it for integration tests, without having to use any Http client nor REST-Assured directly with the big win of creating readable tests.

But there is one more thing to fell in love with Serenity BDD, and it is the reports it generates. If you start using it for BDD tests you'll see how powerful are its reports, being the live-documentation dream a reality, but if you are using just for integration tests, the generated reports are still impressive.

So you can have a quick overview of how your integration tests for a given service is behaving.

Serenity BDD is a really good choice for starting using BDD correctly, providing live-documentation to get the current state of the project and it integrates really well with Cucumber/JBehave as well as Selenium and REST-Assured. But if you are not into BDD or doing BDD-ish, then Serenity BDD is still a solution for just e2e tests (in case of monoliths) or integration tests.

Source code: https://github.com/lordofthejars/ReqRes-Serenity (mvn clean verify -Pdemo)

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Alex

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