Integration testing is one of the three major categories of testing. It falls between unit testing and functional testing. Integration testing is the step when you begin to test the individual parts of a program with each other. This can be a tricky task as there are often times when not all the required parts are developed.
There are three ways of preforming integration testing:
~ Top Down
~ Bottom Up
~ Big Bang
In top down integration testing you start with the top level and work your way to the bottom. As you start with the top many lower levels have not been coded yet. For these you write stubs that hold the palace and provide canned answers. These stubs do just enough so that you can ensure you upper levels work. A disadvantage of this method is the amount of throw away code required for the stubs.
The next approach is bottom up. This is, as it sounds, the opposite of top down. In this method you start by testing the lowest level parts and work your way up. Like in the top down approach there is a certain amount of throw away code required. The difference is instead of stubs you must write drivers. These drivers are used to call the necessary actions to ensure the low levels are working. This method leaves on main issue, design flaws in the project are usually not discovered until a lot of effort has been put in.
The Final method of integration testing known as the big bang approach. This involves waiting for most of the code to be developed and integrating all at once. This is good because there is no throw away code but it becomes very hard to identify issues.
From the blog CS@WSU – :(){ :|: & };: by rmurphy12blog and used with permission of the author. All other rights reserved by the author.