Parallel Testing – A Faster Test Run

Time, being a crucial and finite resource, is critical to the ROI of every business, and hence, 100% test coverage is hardly aimed for. Moreover, with Continuous Integrations, testers and developers are incessantly writing test scripts for varied features. And with different operating systems and a multitude of hardware form factors to test– iPhones and iPads, and over 24000 different Android devices, it is difficult to ensure foolproof software quality assurance. In this scenario, parallel testing comes to the rescue.

With parallel testing, testers can run a test script across multiple browsers, devices, and operating systems at the same time. Moreover, two different versions of the same software can run concurrently with the same input to find out if the legacy and the new system are behaving similar, or differently. The process is automated and often runs on virtual machines. This significantly decreases the cost of maintaining test infrastructure, the cost of long testing cycles and delayed releases, and of course, the cost of detecting bugs later in the SDLC.

When is Parallel Testing Useful

Parallel testing can be quite conducive:

  • When moving from an old software version to a new software version
  • When performing synchronization on two different systems
  • For ensuring cross-platform compatibility of test cases
  • For testing subcomponents of an app simultaneously when there are no dependencies
  • For testing app integrity

Parallel testing is thus an agile testing approach leading to faster testing and quicker turnaround in deployments. SmartBear 2017 State of Software Testing Survey of IT professionals reveals 76% of respondents use parallel testing, with the highest percentage running 2-5 UI tests in parallel at 35%. Participants who do web testing (desktop or mobile testing) are more likely to conduct parallel testing at 77% than those who do not at 66. Besides, respondents who perform end to end software QA testing are 10% more likely to do parallel testing than those focused merely on UI or API.

Let us highlight some of the advantages and disadvantages that parallel testing offers.

Advantages of Parallel Testing

The advantage of using parallel testing is that it:

  • Prevents testers from sequentially running the same test again and again on different machines, but still offers the flexibility to perform sequential tests, if and when needed.
  • Effectively contributes to Agile, DevOps, and Continuous Integrations approach.
  • Ensures rapid deployment and delivery cycles.
  • Provides quick feedback and increased throughput.
  • Enables Scriptless Optimization.
  • Offers robust cross-browser and OS platform validation

Disadvantages of Parallel Testing

Some of the drawbacks of using parallel testing are that:

  • To run parallel testing, it is imperative that testers have complete product knowledge.
  • Parallel testing is an expensive testing technique when we consider the need to replicate resources.


In a nutshell, parallel testing is a process of application testing against several environment configurations concurrently. It can be utilized with ease and utmost efficiency in the cloud, offering significant resource and time reduction. This leads to faster deployments and increased ROI. Given the complexity of testing across a number of browsers, operating systems, and devices, parallel testing is hence a blessing for testers despite some of the challenges it offers. Compatible with Agile, DevOps, and CI approach, parallel testing has definitely taken software quality assurance to a new level, and it is here to stay.

Leave a Comment

Your email address will not be published. Required fields are marked *