Building test cases is about doing your best to find the worst in a program in order to deliver a quality product to the customer. Without a well-designed and executed test plan, the results can be catastrophic and very costly. For example,because of an error in the software, the first flight of the Ariane 5 rocket resulted in its complete destruction and the loss of four satellites at a cost of more than $370 million.

In the U.S. alone, software bugs cost the economy $59 billion2 back in 2002. Clearly, software defects must be found and corrected before unleashing new programs to the customer. This eBook provides you with a basic understanding of software test cases. In addition, the eBook describes proven methods for building test cases that uncover the most defects with the minimum of time, effort and money.

http://www.elementool.com/ebook/SoftwareTestCases.pdf

Its hard to believe that any one incident could cause Google to struggle. But what was it? The crisis in Iran? Global warming? Healthcare?  No, none of these, it was the death of Michael Jackson that cause Google's search engines and video servers to experience such high volume that at times  people were turned away. Go Figure. It's a "Thriller"