What is Ad Hoc Testing?

Performing random testing without any plan is known as Ad Hoc Testing.  It is also referred to as Random Testing or Monkey Testing. This type of testing doesn’t follow any documentation or plan to perform this activity. The testing steps and the scenarios only depend upon the tester, and defects are found by random checking.

Ad hoc Testing does not follow any structured way of testing and it is randomly done on any part of application. Main aim of this testing is to find defects by random checking. Ad hoc testing can be achieved with the testing technique called Error Guessing. Error guessing can be done by the people having enough domain knowledge and experience to “guess” the most likely source of errors.

This testing requires no documentation/ planning /process to be followed. Since this testing aims at finding defects through a random approach, without any documentation, defects will not be mapped to test cases. Hence, sometimes, it is very difficult to reproduce the defects as there are no test steps or requirements mapped to it.

Types of ad hoc testing

Buddy Testing:

Two buddies mutually work on identifying defects in the same module. Mostly one buddy will be from development team and another person will be from testing team. Buddy testing helps the testers develop better test cases and development team can also make design changes early. This testing usually happens after unit testing completion.

Pair testing:

Two testers are assigned modules, share ideas and work on the same machines to find defects. One person can execute the tests and another person can take notes on the findings. Roles of the persons can be a tester and scribe during testing.

Monkey Testing:

Randomly test the product or application without test cases with a goal to break the system.

When to execute Ad hoc Testing?

Ad-hoc testing can be done at any point of time whether it’s beginning, middle or end of the project testing. Ad hoc testing can be performed when the time is very limited and detailed testing is required. Usually adhoc testing is performed after the formal test execution. Ad hoc testing will be effective only if the tester is having thorough knowledge of the system under Test.

This testing can also be done when the time is very limited and detailed testing is required.

Ad Hoc Testing does have its own advantages:

A totally informal approach, it provides an opportunity for discovery, allowing the tester to find missing cases and scenarios which has been missed in test case writing.

  • The tester can really immerse him / her in the role of the end-user, performing tests in the absence of any boundaries or preconceived ideas.
  • The approach can be implemented easily, without any documents or planning.

That said, while Ad Hoc Testing is certainly useful, a tester shouldn’t rely on it solely. For a project following scrum methodology, for example, a tester focused only on the requirements and who performs Ad Hoc testing for rest of the modules of the project(apart from the requirements) will likely ignore some important areas and miss testing other very important scenarios.

When utilizing an Ad Hoc Testing methodology, a tester may attempt to cover all the scenarios and areas but will likely still end up missing a number of them. There is always a risk that the tester performs the same or similar tests multiple times while other important functionality is broken and ends up not being tested at all. This is because Ad Hoc Testing does not require all the major risk areas to been covered.


  • As this type of testing does not follow a structured way of testing and no documentation is mandatory, the main disadvantage is that the tester has to remember all scenarios.
  • The tester will not be able to recreate bugs in the subsequent attempts, should someone ask for issue reproducibility.

Ad hoc testing gives us knowledge on applications with a variety of domains.  And within a short time one gets to test the entire application, it gives confidence to the tester to prepare more Ad hoc scenarios, as formal test scenarios can be written based on the requirement but Ad hoc scenarios can be obtained by doing one round of Ad hoc testing on application to find more bugs, rather than through formal test execution.

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