Model based testing - Osmo

Let's start with tool one: Osmo

Osmo is a java based tool, I started to use it to have more confidence in my tests with connecting them with each other. 

You can download it from here: https://code.google.com/p/osmo/

It is really simple tool. It gives you a few annotations: @Transition, @Guard, @Post, @Pre, etc what you can use to annotate the corresponding methods, and it gives you basic way to generate test scenarios  like completely random, balanced random (so the number of the execution of each transition will be similar).

You can define end conditions, when to finish a test, or a suite (time based, coverage based). And you can easily create your own. It also has other features where you can bind transitions with application features. I won't go into details, only if you are interested in. I will tell you what I tried to achieve with it, and at the end what I decided I will do with it.

First I tried to use it in my API test (it is JSON over HTTP API). Because I was aware of the problem of a too complex model, I decided to cover only the happy paths. So I created a model for each interfaces, I could easily implement the transitions (login, logout, register, create event, etc) and I could use my previously created test user object to track the state. So it was pretty easy, but at the end meaningless... 

why? 

Mostly because the API was so simple and well covered with functional tests, that it was really unlikely that with a slow limited model I could discover anything... Maybe I was wrong, but I already knew there is another tool what I can also use... so I have decided to try out that as well... but it is a different story.

But I really liked the ease of use of OSMO, and I saw its power. So I started to look for a better place for it.

We have another test framework for web GUI. It is based on selenium, and it use jbehave. (maybe I will create another post about how can you integrate another test tool to jbehave). So it is a high level thing, with page object models.

And it was promising... I just closed my eyes, and imagined a test which goes around the whole site randomly, and creates several GUI actions, and continuously checks the states.... and it was a good image. 

Maybe I am alone, but I often faced with issues occur close to but above of the functional tests, like: 

• after the 2nd page of the registration, if you click back, and next, and back and next you will lose your session 
• if you open page A and you go to page B and there you log in, and you click on the promotion, and click back, and log out, and open page A again, your session is still there, or you will get a javascript exception, or whatever...
• you can image more. Common thing: the function works, but the (well, to be honest CRAZY) combination of them does not.

So here, I do not need to be fast, what I want to do is just do whatever I can on the page, and see what happens... So I created a prototype for this, what later we can extend, and basically add another layer of testing. Previously we had tests for pages, and now we can have tests for the whole sites.

And what else can you do with such a model? You can use it for monitoring your application. If you balance the transitions, and make an endless run it will continuously monitor everything (what is in the model) for you. And with the balancing, you can put more focus on the critical components, and less on those things what you do not really care. 

And if your things are in Java, it is really easy to do.

Next time I will tell you about the other model based testing tool....