Broadly applying virtualization technology to test can simplify administration, improve process scalability and reduce workloads
BY DAVID GEHRINGER
Fanfare, Mountain View, CA
http://www.fanfaresoftware.com
Virtualization has been a growing trend in instrumentation and enterprise IT for several years, and it continues to gain momentum as new uses for this technology emerge. Virtualization’s acceptance largely reflects the convenience of having various versions (instances) of an entity defined by software. These versions can either coexist, or quickly change to facilitate the users needs, thus simplifying administrative tasks, improving the scalability of a process or operation, and reducing workloads.
Today in test and measurement, there is a completely new take on virtualization. Referred to as the virtual testbed (VTB), its capabilities deliver considerable value to testing organizations by enabling designers and test engineers to build test cases before the devices to be tested actually exist, thereby beginning the quality process months earlier.
Users can also leverage a VTB for test development by using virtual replicas not only of real devices but of costly test equipment as well. As a result, organizations can trim future capital expenditures by improving utilization of their lab assets and infrastructure, boosting test engineer productivity by permitting offline or remote work, and enabling earlier testing, accelerating time to market for new products and services.
How does VTB work?
Nearly all device and system tests are composed of issuing a command to a device and then using the information in its response to determine if pass/fail criteria are met. For a very simple example, let’s say I want to verify that the software version is “12.2” and document that for the test. I would issue a command such as “show version” and then the device would return a response showing many lines of information and one piece of data in the response would be the software version. I could then use the analysis rules in my test automation software to automatically check the version number against the expected value of “12.2” and issue the appropriate pass/fail indication.
Now let’s say I know version 12.3 is coming out and I want to get a jump start on testing. I would open my test automation software’s VTB and create a virtual response by either cutting and pasting the current response and modifying it, or creating an entirely new response from scratch. (Similar to Microsoft Word, I could edit/modify an existing document or create a new one.)
A virtual testbed lets users build test cases before devices exist.
In the example above, I create a new response for the “show version” command, and in this case the new response would be “12.3.” Now I can create a test case using the virtual response and add an analysis rule looking for “12.3” for pass/fail criteria. Voila! I have created an automated test case for a device that isn’t even in prototype. And once the prototype is ready, a single click would alter the test case from running against the VTB to running against the real device.
While this is an over-simplified example, it shows how VTB can be used for building test cases before devices exist. The same philosophy lets users create test cases that leverage a VTB for test development, saving the resources of expensive labs by using virtual replicas of real devices and test equipment.
VTB benefit analysis
In today’s harsh economic climate budgets are being slashed while the amount of work remaining continues to grow. This is due in large part to ever-increasing device complexity and the desire for companies to get products and services to market faster. At the same time , multi-million dollar labs are being under-utilized, sitting idle, or being used for test development and thus not available for peak testing times.
VTB changes this by allowing the creation of virtual devices and testbeds that can be used to create, edit, and validate test cases. Once the test case has been proven to work, the test can be run against real lab equipment.
With mobile computing, more and more users are working in locations other than the office, and as a result may not have access to the lab to continue working on their tests. With VTB, test engineers now have the ability to create virtual devices, so they can remain productive on a plane or at a remote location.
Today, in world-class organizations, test plans are started the moment feature specs are approved – but actual test creation cannot start until a prototype unit is created. These prototypes might consist of a physical board and software. The advantage of VTB is that a virtual device can be created ahead of the prototype. Test engineers can use the VTB to develop tests weeks or months ahead of schedule, and start testing the day prototype is ready. ■
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