If you ask several software test leads or managers “What makes a great tester?” Each will most likely give you many varied answers but the following will be common among all:
Communication skills; In particular the ability to clearly and accurately describe any and all steps leading up to defective behavior in the software.
However, no matter how good your observation or note taking skills are it is impossible to observe and note everything.
What if you had a fairly easy, inexpensive and non-intrusive method that would allow all your testers to inherit the benefits of the very best observational and note taking skills? Well, there is such a thing. We call it the system test “black box”.
Using off the shelf technology, we have put together a set up that records all user activity leading up to a defect or crash/hang in the software. Being able to replay user interaction allows you to notice things you didn’t spot the first time, as well as freeing up more of your capacity as you’re not distracted by trying to take notes on your actions. (Humans have limitations, both in attention and memory – let machines do what they’re best at and free your testers to exercise their creativity and analysis skills.)
Functional Overview
The VGA video from the PC is fed to the video converter box which converts the VGA signal to RS170. The RS170 signal is then input to the DVR. Thus everything that is displayed on the PC monitor is being recorded by the DVR on to an SD card. In addition to converting the VGA signal to RS170, the video converter box also passes the original VGA signal thru to an output that can be connected directly to the monitor. Thus you have essentially tapped into and are recording the PCs monitor output. And this is being accomplished without having to run any recording software on the PC or adding any additional load to the CPU.
Limitations
There is one limitation worth noting. RS170 video is not known for it’s high resolution/video quality. If your monitor is set for a resolution much higher than 1024×768, the resulting recorded video may be of inadequate quality to be viewed comfortably. We have found that setting the monitor resolution to 1024×768 is a good compromise between reasonable monitor resolution and adequate recorded video quality.
Benefits
The DVR and video interface box are small and light and can be tucked away and forgotten until a crash/hang or defect occurs. At that time the recording can be stopped and reviewed to determine the user interaction leading up to the event.
The size of the SD card determines the duration of video that is recorded. You may want to use a smaller SD card to loop on recording just a few minutes of video. On the other hand, you may choose a larger SD card to record several hours of video. We have found a smaller SD card useful for interactive testing while a larger SD card has proven more useful for extended automated testing. For example, if the software crashes/hangs during the night, you can extract data from the video recording as to what time the crash occurred and what functionality was being exercised at the time of the crash/hang.
When a crash occurs it’s always good to have a “black box” recording of the events to help determine root cause. An example recording can be viewed below. It’s a bit long, but watch out for the crash at 3:32:39 (by the timestamp).
Source: http://www.ministryoftesting.com/2013/09/a-black-box-for-software-testing/