Should Developers Test Their Own Code Or Do We Need A Separate Testing Team?

Should developers test their own code? In Software Development, developers play a major role as they are the ones who design, code, and build the software. Apart from this, developers also do testing. Developers are often asked to perform “white box” testing or in simple words the tests that involves dealing directly with the code. One of such tests that they perform is called Unit testing.

Developers may also perform Integration Testing. These testing types will verify the functionality, performance and reliability of the program, but doing unit testing and integration testing may not be enough and may not ensure that the program could catch every catchable error.

What does it require to fully test the program and can the developer test their own code?

It has not been proven that developers who build and code the program can substitute a tester and follow a detailed test plan. As they say, “Good Developers may not be Good Testers”. Below are the pros and cons if the developer will test their own program.

Pros:

1. The developer will be familiar with the program.
2. The developer will have the satisfaction seeing the program pass the required specifications.

Cons:

1. Misunderstandings on the business and technical requirements will not be detected because the developer will tend to assume that what he said to the other person is correct and/or he will treat it as a functionality or limitation of the program. Because of this, improper use of the development process may not also be detected.
2. The developer will tend to be over optimistic on the program. Because of this, he might overlook other details of the program or will skip bugs.
3. Some parts of the program will not be tested because once the developer has seen that a certain part is working, he will not re-test it as he will always assume that it’s already working properly and doesn’t affect other process.

Based on the facts above, developers tend to overlook the other parts of the program, as their goal is to make it perfect. Developers can test few exceptional conditions and know the important details of the program. They can also do basic testing and verification, but unlike the software testers, their goal is to break the program and find defects. Testers also do it continuously, while developers find it time consuming as they’re tempted to improve the system and documentation rather than finding defects on the program.