ALM Best Practices

What is Service Virtualization?

 

We’ve been fielding a lot of questions lately about service virtualization and how this relates to what Parasoft is calling "Application-Behavior Virtualization."  Here are some explanations…

Service Virtualization Definition

In a nutshell, service virtualization provides teams easy access to the constrained components that impede development and testing.  This eliminates scheduling constraints by providing ubiquitous access to an accurate emulated test environment.  And it eliminates process bottlenecks by providing rapid access to evolving, unavailable, or otherwise difficult-to-access dependent systems. 

According to Wikipedia's service virtualization entry:

Service virtualization emulates the behavior of software components to remove dependency constraints on development and testing teams. Such constraints occur in complex, interdependent environments when a component connected to the application under test is:

• Not yet completed

• Still evolving

• Controlled by a third-party or partner

• Available for testing only in limited capacity or at inconvenient times

• Difficult to provision or configure in a test environment

• Needed for simultaneous access by different teams with varied test data setup and other requirements

• Restricted or costly to use for load and performance testing

Service virtualization emulates only the behavior of the specific dependent components that developers or testers need to exercise in order to complete their end-to-end transactions. Rather than virtualizing entire systems, it virtualizes only specific slices of dependent behavior critical to the execution of development and testing tasks. This provides just enough application logic so that the developers or testers get what they need without having to wait for the actual service to be completed and readily available.

For instance, instead of virtualizing an entire database (and performing all associated test data management as well as setting up the database for every test session), you monitor how the application interacts with the database, then you emulate the related database behavior (the SQL queries that are passed to the database, the corresponding result sets that are returned, and so forth).

Service Virtualization and Application-Behavior Virtualization

The term Application-Behavior Virtualization is a related term that Parasoft has introduced to describe our service virtualization capabilities, as implemented in Parasoft Virtualize. Why not just call it "service virtualization"? Two key reasons:

• Because the term "service virtualization" was initially used to describe using virtual endpoints to shield service infrastructure details from web service consumers.

• To emphasize that it's possible to virtualize the behavior of much more than web services. Using Application-Behavior Virtualization/Service Virtualization, you can emulate behavior across composite applications—including interactions with databases, mainframes, 3^rd-party systems, ERPs, ESB/JMS, legacy systems, and other composite application components.

 

Next week, we'll cover how service virtualization/Application-Behavior Virtualization relates to hardware and OS virtualization.

 

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If you’d like an overview of how Parasoft's service virtualization/Application-Behavior Virtualization provides easy access to the constrained components that impede development and testing, read our Service Virtualization eBook or visit the Parasoft Virtualize page.