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What is isolation testing in software testing?

Hammad Nasir

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Software testing is an essential part of the Software Development Life Cycle (SDLC) to ensure the quality of a software product. Out of the several software testing techniques employed, in this shot we will discuss the isolation testing technique.


In isolation testing, the whole system is broken down into smaller subsystems or modules. Then, these subsystems or modules are tested independently to verify the result.

The following diagram provides further clarity:

The need for isolation testing

Isolation testing is needed for unresolved bugs or to locate bugs that are undetectable. Therefore, isolation testing can be performed at any point in the SLDC. Furthermore, isolation testing is performed in the following testing processes as well:

Isolation testing in performance testing

In performance testing, the testers gauge the performance of the software using various techniques. Isolation testing comes in handy here since the testers repeatedly execute the buggy task, and by isolating different modules in every stage, they are able to identify the root domain of the bug.

Isolation testing in unit testing

Unit testing is similar to isolation testing, as the former also involves testing smaller components of the system. Since isolation testing works by breaking down the system into really small modules, the testers are able to validate a unit quicker.


  • The error is guaranteed to be pinpointed using this approach.


  • It is a very time-consuming process.
  • It is an expensive method since the whole system has to be broken down to the atomic level.


software testing


Hammad Nasir
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