Black box testing is a process by which software products are tested. Agile defines this testing technique as any type of testing that requires or could be done with the person taking the test being unaware of what kind of software is making the product work. Software tests that look to integrate, testing functions and/or systems, and meant to see if the system passes acceptance requirements are all done using the black box approach.
One big benefit of using the black box testing approach is to go through large segments of code. When working on a deadline, it is often more effective to run through 10,000 or 20,000 lines of code in one large test. This offers the ability to find and pinpoint different issues that could have been missed if the code were tested one line at a time, and half of the code is missed before the deadline comes.
Another benefit to any black box test is to allow pretty much anyone to take part in the testing. The tester does not need to know about code and how to write it to par take in the testing when black box is used. For example, a lot of people know how to play the card game Phase 10. If they don’t, it’s easy enough to learn how. Say the software is being tested to make an online, multiplayer version of the game. The manufacturer has put out the beta version for mass testing – thinking there is a problem with the way the code has been programmed. Thousands of players write in to say that they all finish in 10 rounds, regardless of if they actually played each phase. With the problem found, it can now be solved.
Speaking of non-technical testers, the testers can be those who are going to use the software in the end, anyway. Returning to the Phase 10 example, there are plenty of players who would love the challenge of playing online with a completely fair game. Now, suppose that a programmer accidentally programmed the game to let Player 2 – regardless of who they are – win every round and every game by giving them all the wilds in the deal. Players catch on and start to let the developer know. They are the ones playing the game – if they know Player 2 will always win, they won’t play.
These tests are also able to be reproduced. Instead of having everyone run the same test, there can be thousands of people taking one, and more taking a different test. This allows different areas of code to be tested, and allows the major aspects of the code to be tested for issues. While not every single test will produce a fault or issue, it’s helpful to run a few of these at a time.
Black box testing has other advantages as well, but these are the most beneficial reasons to run testing via the black box method.