Exploratory Testing: Complete Guide with Session Based Testing

Exploratory Testing: The Complete Guide to Session-Based Test Management (SBTM)

In the fast-paced world of software development, where requirements shift and deadlines loom, traditional scripted testing can sometimes feel like navigating a maze with an outdated map. Enter exploratory testing—a powerful, intellectually stimulating approach that empowers testers to simultaneously design and execute tests, leveraging their skills, intuition, and curiosity to uncover critical bugs that scripted checks often miss. This guide dives deep into the art and science of exploratory testing, with a particular focus on the structured, measurable framework of Session Based Testing (SBTM). We'll move beyond ad-hoc testing myths, explore practical techniques, and show you how to implement a disciplined, results-driven exploratory practice.

What is Exploratory Testing? Beyond Ad-Hoc Testing

Exploratory Testing (ET) is a hands-on approach where the tester's personal freedom and responsibility are paramount. Unlike scripted testing, where steps are pre-defined, ET involves dynamically creating tests, learning about the software in real-time, and using those insights to design new, better tests. It's a cyclical process of exploration, learning, and test design.

Exploratory Testing vs. Ad-Hoc Testing: Clearing the Confusion

Many conflate exploratory testing with ad-hoc testing, but there's a crucial difference. Ad-hoc testing is informal, unstructured, and often unrepeatable—it's "clicking around." Exploratory testing, especially when framed within SBTM, is a structured, accountable, and documented process.

• Ad-Hoc Testing: Unplanned, undocumented, unrepeatable. Goal is often just "to see what breaks."
• Exploratory Testing (with SBTM): Mission-focused (via charters), time-boxed, documented, debriefed, and its results are analyzed for trends.

The Framework: Session Based Test Management (SBTM)

Pioneered by Jonathan and James Bach, Session Based Test Management (SBTM) is the methodology that brings discipline to exploratory testing. It organizes testing into uninterrupted, focused work periods called "sessions," making the work quantifiable and its value clear to stakeholders.

Core Components of a Testing Session

Each session is built on three foundational pillars:

1. The Charter: The mission statement for the session. It defines the what and why, not the how. (e.g., "Explore the new payment gateway integration to assess transaction reliability under slow network conditions.").
2. The Time Box: A focused, uninterrupted period of testing, typically 60-120 minutes. This creates a sense of urgency and helps in effort estimation.
3. The Reviewable Results: The tangible output of the session, primarily the Session Sheet, which includes notes on bugs, issues, data files, and a narrative of what was done.

Crafting the Perfect Test Charter

The charter is the cornerstone of effective SBTM. A well-written charter provides direction without stifling creativity.

Elements of an Effective Charter

• Target: What feature, component, or user story are you exploring?
• Resources: What tools, data, or build will you use?
• Information: What kind of information are you looking for? (e.g., "identify performance bottlenecks," "assess usability for first-time users").
• Test Design Ideas: Optional prompts or heuristics to kickstart thinking (e.g., "use the CRUD heuristic," "consider boundary values for input fields").

Example Charter: "Explore the user profile editing functionality (Target) in the mobile app v2.5 (Resources) to evaluate data validation and error handling (Information). Consider inputs with special characters, extremely long strings, and SQL-like syntax (Test Design Ideas)."

Documentation & Reporting: The Session Sheet

Documentation is what transforms exploration from a casual activity into a professional practice. The Session Sheet is your primary artifact.

What to Record in Your Session Sheet

• Charter: The session's mission.
• Tester & Date: Basic accountability.
• Task Breakdown: How was the session time spent? (e.g., 40% setup, 30% testing feature X, 20% bug investigation, 10% note-taking).
• Bugs & Issues: Concise descriptions with clear steps to reproduce, severity, and any supporting evidence (screenshots, logs).
• Opportunities & Ideas: Notes on usability improvements, feature suggestions, or areas needing more scrutiny.
• Narrative: A brief prose summary of the tester's journey, thought process, and key observations.

Powerful Exploratory Testing Techniques & Heuristics

To be effective, exploratory testers use mental models and heuristics as "tools of thought." Here are some of the most powerful:

1. Tour-Based Techniques

Structure your exploration by taking guided "tours" of the application:

• Guided Tour: Follow a user persona's likely path.
• Money Tour: Test the feature that directly generates revenue.
Test the feature that directly generates revenue.
• Anti-Tour: Deliberately avoid the happy path.
• Back Alley Tour: Focus on error messages, logs, and settings menus.