How do you stress test your own software?

Question

I've been working on an app, by myself, and I am at a stage where everything works great--as long as the user does everything he or she is supposed to do. :-) The software needs more testing to see how robust it is, how well it works when people do things like click the same button repeatedly, try to open the wrong kind of files, put data in the wrong places, etc.

I'm having a little trouble with this because it's a bit difficult for me to think in terms of using the application incorrectly. These are all edge cases to me. Still, I'd like to have the application as stable and well tested as possible before I start giving it to beta testers. Assuming that I am not talking about hiring professional testers at this point, I'm curious whether y'all have any tips or systematic ways of thinking about this task.

Thanks, as always.

Answer 1

Well it sounds like you are talking about 2 different things "Testing your application's functionality" and "Stress testing"(which is the title of your question)

Stress testing is when you have a website, and want to check that it can server 100,000 people at the same time. Seeing how your application performs under stress. You can do this a number of ways, e.g by recording some actions and then getting a number of agent machines to hit your application concurrently.

This questions sounds more like a Quality Assurance question. That is what testers / beta testers are for. But there are things that you can do yourself to validate your application works the best it can.

Unit testing your code would be a good start, it helps you to try and find those edge cases. If your method takes in things like ints, try passing in int.max, int.min, and seeing what blows up. Pass nulls into everything. If you are using .Net you might want to look at PEX, it will go through all the branches/codepaths that your application has. That might help you to further refine your unit tests to test your application the best you can.

Integration tests, see what happens end to end for some of your usual things. This will help you 'find bugs' as you are developing later.

Those are some quick tips on things you can do yourself to try and find edge cases that you may have missed. But yes, eventually you will need to pass your app off to someone else to test. Just make sure that you have covered off as much as you can before it hits them :-)

Answer 2

Make sure you have adequate code coverage in your unit tests and integration tests.

Use appropriate UI validation, and test combinations that can break it.

I have found that a well-architected application that reduces the number of possible permutations in the UI (ways the user can break it) helps a lot. Design patterns like MVC can be especially useful in this regard, since they make your UI veneer as thin as possible.

Answer 3

Automation.

(Re)Factor your code so that another program can throw user-events at it. Create simple scripts of user events and play them back to your program. Capture events from beta users and save those as test scripts (useful for reproducing problems and checking for regressions). Write a fuzz-tester that applies small random changes to the scripts and try them against your program as well.

With this kind of automation you can stress and application and find glaring problems like caches and memory leaks. It won't test the actual functionality. For functionality, unit tests can be helpful. There are a ton of unit testing frameworks out there to try. Pick something useful, learn to write good tests, and integrate them into your build process.