Exploratory Testing: Concepts, Evolution, and Practical Techniques

Let me write an article about Exploratory Testing (ET); the topic seemed huge at first, but after reading many sources I decided to reflect on how I use ET in functional testing based on my own work experience.

From a complete beginner to being able to independently test an app, I will share how I developed these skills.

What is Exploratory Testing? It is a testing mindset that requires QA to design and execute simultaneously, without a predefined test plan or test cases. In one sentence: a testing mindset of “design‑while‑execute”. In my view, it boils down to four characters: fill‑the‑gaps .

ET covers what automated tests and scripted cases miss, acting as a supplement to other testing methods. In foreign companies ET can account for over 90% of testing; in my early career it was about 10%, later 30%, and now exceeds 50%, with some projects relying on ET for up to 80% of defect discovery.

The rapid product iteration drives the growing importance of ET. Short development cycles and frequent requirement changes mean that test cases cannot keep up, so QA must constantly explore, stay curious, and adapt.

How to Perform Exploratory Testing? ET execution can be divided into four categories: deep free‑form testing, scenario‑based traversal, strategy‑driven extrapolation, and feedback‑driven iteration.

Below are four concrete examples.

1. Deep Free‑Form Testing

Consider a splash screen with various advertisement channels. Simple test points include skip button, link navigation, and display. Using ET, we can also test interaction interruptions (back, home, lock, incoming calls), backend configuration errors, memory leaks, and compatibility.

2. Scenario‑Based Traversal

For a search feature, beyond basic validation, ET explores UI variations (night mode, full‑screen, no‑image, rotation), multi‑touch actions, input edge cases (max length, spaces, illegal characters, copy‑paste, language switches), and external link conflicts.

3. Strategy‑Driven Extrapolation

A simple 404 page has basic checks (page loads, button works, menu works). By extrapolating, we discover that if the bookmark button is disabled, related functions like save page and find‑in‑page should also be disabled, even on about:blank pages.

4. Feedback‑Driven Iteration

On an information‑flow page, short videos auto‑play silently. Rapid scrolling can cause crashes because videos start playing before the previous one stops. Further feedback reveals that videos replay when the view re‑enters the viewport after a slight scroll.

These examples show that the richness of testing is limited only by the breadth and depth of our thinking and product insight.

Techniques for Cultivating ET Skills

1. Foundation – Exhaustive Enumeration Start by listing every possible test point for a given environment (e.g., network types: 2G/3G/4G, Wi‑Fi, guest Wi‑Fi, airplane mode, dual‑SIM switching, unstable networks, carrier‑specific settings, proxies, etc.).

2. Quantification – Incremental Improvement Set measurable daily goals such as adding new test cases, extending test time, or expanding the scope of exhaustive lists.

3. Learning – From Vagueness to Extrapolation Move from unclear understanding to information gathering, analysis, summarization, verification, and finally the ability to extrapolate findings.

4. Efficiency – Experience‑Guided Prioritization Use experience to focus on high‑impact combos (e.g., concurrency, extreme conditions) and de‑prioritize low‑value cases, balancing thoroughness with realistic effort.

In conclusion, let us remember: “Exploration is a method, a process, a mindset, and a spirit.” Be a QA who stays curious about everything.

Wishing everyone a smooth 2017 and a Happy New Year!