What is exploratory testing?

Exploratory testing is a vital tool in your armory. It involves you using a new feature in an ad hoc, unstructured way to quickly find issues and understand its workings. It is typically used early in the test cycle to achieve three main goals: to let you understand the feature you are testing, to discover any tools or knowledge you need, and to find blocking bugs that may delay the testing later on.

In exploratory testing, the test design, implementation, and interpretation are conducted simultaneously. This is also known as ad hoc testing, which has been frowned upon due to its unstructured format. However, it is a valuable stage in a project if deployed alongside other testing techniques. In a large project, it can be used early on to help plan more comprehensive tests, or if deadlines are tight, exploratory testing might be the only testing there’s time for.

In an ideal cycle, the team will plan both the feature and its testing at the start of development. In that case, exploratory testing enhances the test plans that already exist. In other development teams, testers are involved later in the project and may only plan the testing in earnest once the first version is already running. In both cases, exploratory testing is a necessary step for you to see a new feature working in practice so that you can write detailed test plans with the exact behavior in mind.

Exploratory testing must be performed manually so that you can get your hands on the new feature and see what inputs and outputs are available. Other parts of testing can be run manually or with automation, but exploratory testing must be manual because the main aim isn’t to find bugs but to understand the feature. Based on that understanding, you can plan further testing.

Not everyone can perform exploratory testing. In particular, it needs input from someone other than the developer who worked on the code. The developer should ensure the feature is working for them, but exploratory testing shows whether it can work in another environment for another engineer. That is the second goal of exploratory testing: to find issues significant enough to block further tests.

If the new feature doesn’t run in the test environment, if a page throws an error, or parts of the functionality aren’t available, that will block testing of those whole areas. Exploratory testing can quickly find those issues so that they can be fixed early in the development cycle and not cause delays later on.

First, we’ll consider the advantages and disadvantages of exploratory testing, along with alternative approaches that perform similar roles.