hurl/docs/tutorial/your-first-hurl-file.md
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Your First Hurl File

Throughout this tutorial, we'll walk through the creation of multiple Hurl files to test a basic quiz application. We'll show how to test this site locally, and how to automate these integration tests in a CI/CD chain like GitHub Action and GitLab CI/CD.

The quiz application consists of:

  • a website that lets people create or play a series of quizzes
  • a set of REST APIs to list, create and delete question and quiz

With Hurl, we're going to add tests for the website and the APIs.

Prerequisites

Well assume you have Hurl installed already. You can test it by running the following command in a shell prompt (indicated by the $ prefix):

$ hurl --version

If Hurl is already installed, you should see the version of Hurl. If it isn't, you can check Installation to see how to install Hurl.

Next, were going to install our quiz application locally, in order to test it. We are not going to build our application from scratch, in order to focus on how to test it.

Hurl being really language agnostic, you can use it to validate any type of application: in this tutorial, our quiz application is built with Spring Boot, but this could as well be a Node.js or a Flask app.

Our quiz application can be launched locally either:

  • using a Docker image
  • directly using the jar of the application

If you want to use the Docker image, you must have Docker installed locally. If it is the case, just run in a shell:

$ docker pull ghcr.io/jcamiel/quiz:latest
$ docker run --name quiz --rm --detach --publish 8080:8080 ghcr.io/jcamiel/quiz:latest

And check that the container is running with:

$ docker ps
CONTAINER ID   IMAGE                         COMMAND                  CREATED         STATUS         PORTS                                       NAMES
922d387923ec   ghcr.io/jcamiel/quiz:latest   "java -jar app/quiz.…"   8 seconds ago   Up 6 seconds   0.0.0.0:8080->8080/tcp, :::8080->8080/tcp   quiz

If you want to use the jar application, you must have Java installed locally. If it is the case, download the jar application from https://github.com/jcamiel/quiz/releases/latest and run in a shell:

$ java -jar quiz-0.0.2.jar 

Either you're using the Docker images or the jar app, you can open a browser and test the quiz application by typing the url http://localhost:8080:

Quiz home page Quiz home page

Our quiz app: we've only secured a budget for integration tests and nothing for the site design...

A Basic Test

Next, were going to write our first test.

  1. Open a text editor and create a file named basic.hurl. In this file, just type the following text and save:
GET http://localhost:8080

This is your first Hurl file, and probably one of the simplest. It consists of only one entry.

An entry has a mandatory request specification: in this case, we want to perform a GET HTTP request on the endpoint http://localhost:8080. A request can be optionally followed by a response description, to add asserts on the HTTP response. For the moment, we don't have any response description.

  1. In a shell, execute hurl with basic.hurl as argument:
$ hurl basic.hurl
<!doctype html>
<html lang="en">
<head>
    <meta charset="utf-8">
    <title>Welcome to Quiz!</title>
<!--    <link rel="stylesheet" href="style.css">
    <script src="script.js"></script>-->
</head>
....
</html>

If the quiz app is running, you should see the content of the html file at http://localhost:8080. If the quiz app is not running, you'll see an error:

$ hurl basic.hurl 
error: HTTP connection
  --> basic.hurl:1:5
   |
 1 | GET http://localhost:8080
   |     ^^^^^^^^^^^^^^^^^^^^^ (7) Failed to connect to localhost port 8080: Connection refused
   |

As there is no response description, this basic test only checks that an HTTP server is running at http://localhost:8080 and responds with something. If the server had a problem on this endpoint, and had responded with a 500 Internal Server Error, Hurl would have just executed successfully the HTTP request, without checking the actual HTTP response.

As this test is not sufficient to ensure that our server is alive and running, we're going to add some asserts on the response and, at least, check that the HTTP response status code is 200 OK.

  1. Open basic.hurl and modify it to test the status code response:
GET http://localhost:8080
HTTP/1.1 200
  1. Execute basic.hurl:
$ hurl basic.hurl
<!doctype html>
<html lang="en">
<head>
    <meta charset="utf-8">
    <title>Welcome to Quiz!</title>
    <link rel="stylesheet" href="style.css">
    <script src="script.js"></script>
</head>
....
</html>

There is no modification to the output of Hurl, the content of the HTTP request is outputted to the terminal. But, now, we check that our server is responding with a 200 OK.

By default, Hurl behaves like curl and outputs the HTTP response. This is useful when you want to get data from a server, and you need to perform additional steps (like login, confirmation etc...) before being able to call your last request.

In our case, we want to add tests to our project, so we can use --test command line option to have an adapted test output:

  1. Execute basic.hurl in test mode:
$ hurl --test basic.hurl
basic.hurl: Running [1/1]
basic.hurl: Success (1 request(s) in 8 ms)
--------------------------------------------------------------------------------
Executed files:  1
Succeeded files: 1 (100.0%)
Failed files:    0 (0.0%)
Duration:        7 ms
  1. Modify basic.hurl to test a different HTTP response status code:
GET http://localhost:8080
HTTP/1.1 500
  1. Save and execute it:
$ hurl --test basic.hurl
basic.hurl: Running [1/1]
error: Assert status code
  --> basic.hurl:2:10
   |
 2 | HTTP/1.1 500
   |          ^^^ actual value is <200>
   |

basic.hurl: Failure (1 request(s) in 8 ms)
--------------------------------------------------------------------------------
Executed files:  1
Succeeded files: 0 (0.0%)
Failed files:    1 (100.0%)
Duration:        13 ms
  1. Revert your changes and finally add a comment at the beginning of the file:
# Our first Hurl file, just checking
# that our server is up and running.
GET http://localhost:8080
HTTP/1.1 200

Recap

That's it, this is your first Hurl file!

This is really a basic test, but it shows how powerful Hurl's simple file format is. We're going to see in the next section how to improve our tests while keeping it really simple.