How to make/build larger Selenium Test Suites?
It is very much possible to run very large number of selenium tests. In my organization we run around 200,000 to 300,000 tests per day across multiple websites. So yes its possible.
Note:- I code in JAVA and all the info below is from a JAVA perspective.
For a large scale testing using selenium to be successful, I would say it needs 3 basic components
- The infrastructure
- A good framework and easily maintainable code
- Easy and clear reporting
Infrastructure
Your infrastructure should be able to support the huge load. We use selenium grid (if you are using Selenium 2 then its called as Grid 2.0) to achieve this. Selenium Grid allows us to run multiple tests in parallel and across multiple browsers. We use our own servers in which virtual machines are deployed to support this testing. There are vendors like Saucelabs.com to whom you can outsource the infrastructure maintenance.
Framework and testcode
Your framework must support multithreading and it should be threadsafe to utilize the selenium grid features. We use JAVA to make sure this happens. To run the tests in parallel testNG is used. testNG can run multiple methods in parallel and all these tests will point to one single Hub. The hub would then distribute all these tests against multiple Remote Controls(RCs) connected to it.
When you have large set of tests, maintenance is inevitable. To reduce the rework effort due to a change in the application, its always better to follow the Page Object Model. Page object essentially means - each page in your application should have a corresponding class in your code. You will define all the elements and functions that can happen in that page in this class. This is a very modular and reusable structure. You can google for pageobject model and you will find many articles.
Reporting
Its great to run 200,000 tests per day, but if you cannot showcase what failed and what passed in an easily accessible method your automation tests will not be of much use. There are multiple methods for this. From HTML reporting to building custom dashboards to show the results.
Once you have all these in place, then the only thing you will need is a tool to keep these tests running continuously. You can use any CI (continuous integration) tool to achieve this. Jenkins , Hudson , cruisecontrol are few of the CI tools that are mostly used.