Simplify Enterprise Testing With the Right Tools: Two Case Studies (Continued)

User-Friendliness Is Important
Ease of use is important in selecting a test tool. "It requires experience with the business and its goals to design tests," Deloney points out. They find the Empirix tools to be user-friendly, making it easy to enter test scripts.

During testing, the tools are able to simulate subtle behavior, such as the think-time it takes a user to decide what to do next, or the random delays between the advent of new users. As the script plays back, the tool can easily identify where any difficulties arose. This allows testers to tweak the script to expose any issues with the system.

In addition to testing the external demands on the system, Block also tests internal system processes such as load balancing. The ideal is to distribute user load across many servers, so that no one server becomes overwhelmed. In reality, there may be difficulties in assigning or relinquishing memory, or in accessing storage, depending on server load. Careful testing should reveal where the bottlenecks are. Even the impact of unforeseen events—such as pulling the plug on a server—must be simulated and evaluated.

Block uses careful monitoring tools OneSight and e-Manager to look for specific indicators, including CPU utilization, memory usage, database locks, and table contention. "Typically, we start with a small subset of the entire system," comments Deloney. Then the testers move up in both the breadth of the system tested and the user demand on the system, including batch processes.

Since systems change, tests must change with them. While it is often possible to reuse and rewrite test scripts, it is often necessary to create new ones. Naturally, you want a tool that makes that as easy as possible. "We have moved from Windows NT to 2000 to XP and now to .NET, with no problems," notes Deloney. It is important for tool vendors themselves to keep pace with changes in technology, incorporating them rapidly into their products. Response to the customer is essential.