When automating tests, avoiding creating brittle tests are very important. In my experience, this something that can easily happen when using Selenium if you don’t take special care.
For instance, when locating elements on the page, you typically would like to refer to them using IDs. However, can you be sure that the IDs stay the same at all times? No. This problem becomes appearent when creating ASP.NET applications in Visual Studio. Visual Studio automatically generates what is called the Client ID for a control, based on its location in the control hierarchy. This id is rendered as both the id attribute and name attribute of an HTML element. For example, an ID might look like this:
As a consequence, if you move a control to another place in the control hierarchy, the ID will be different. If you have referred to this ID in your Selenium test, it will break! Not good.
In order to fix this situation, I created a locator that does a partial match on the element id attribute.