Exploratory Testing

Detailed explanation

Exploratory testing is a dynamic and iterative approach to software testing that emphasizes learning, discovery, and adaptation. Unlike scripted testing, where test cases are pre-defined, exploratory testing encourages testers to simultaneously design and execute tests based on their understanding of the system under test (SUT) and their evolving insights. This approach is particularly valuable when requirements are vague, incomplete, or rapidly changing, and when the tester possesses significant domain knowledge.

The Core Principles

At its heart, exploratory testing revolves around three key elements:

• Learn: Testers actively learn about the SUT, its functionalities, and its intended use. This learning process involves exploring the application, reading documentation, and collaborating with developers and stakeholders.
• Design: Based on their understanding, testers design tests on-the-fly. These tests are not written down in advance but are conceived and executed in real-time.
• Execute: Testers immediately execute the designed tests, observing the system's behavior and looking for unexpected results, errors, or inconsistencies.

These three elements form a continuous cycle of learning, designing, and executing, allowing testers to adapt their approach as they gain more knowledge about the SUT.

When to Use Exploratory Testing

Exploratory testing is most effective in the following scenarios:

• Limited or Unclear Requirements: When requirements are poorly defined or constantly evolving, exploratory testing allows testers to adapt and discover potential issues that might be missed by scripted tests.
• Tight Deadlines: Exploratory testing can be a faster way to identify critical bugs compared to writing detailed test cases, especially when time is limited.
• Complex Systems: In complex systems with numerous interactions and dependencies, exploratory testing can help uncover unexpected behaviors and edge cases.
• Experienced Testers: Exploratory testing relies heavily on the tester's skills, knowledge, and intuition. It is best suited for experienced testers who have a deep understanding of the domain and testing principles.
• Complementary to Scripted Testing: Exploratory testing can be used in conjunction with scripted testing to provide a more comprehensive testing strategy. Scripted tests can cover the core functionalities, while exploratory tests can focus on areas that are not well-defined or require more in-depth investigation.

Practical Implementation and Best Practices

To effectively implement exploratory testing, consider the following best practices:

• Chartering: Before starting an exploratory testing session, define a clear charter that outlines the scope, objectives, and focus areas of the session. A charter helps to guide the tester's exploration and ensure that the testing efforts are aligned with the overall goals. For example, a charter might be "Explore the user registration process to identify potential security vulnerabilities."
• Timeboxing: Set a time limit for each exploratory testing session. This helps to maintain focus and prevent testers from getting lost in irrelevant details. Common timebox durations are 60-90 minutes.
• Note-Taking: Meticulously document the testing process, including the tests performed, the observations made, and any issues encountered. This documentation is crucial for reproducing bugs, sharing knowledge, and improving the testing process. Tools like session-based test management (SBTM) can be used to facilitate note-taking and session management.
• Debriefing: After each exploratory testing session, conduct a debriefing to discuss the findings, share insights, and identify areas for further exploration. This debriefing helps to consolidate knowledge and improve the effectiveness of future testing sessions.
• Tool Support: Utilize tools to support exploratory testing, such as screen recorders, bug tracking systems, and session-based test management tools. These tools can help to streamline the testing process and improve the quality of the documentation.
• Collaboration: Encourage collaboration between testers, developers, and stakeholders. This collaboration can help to improve the understanding of the system and identify potential issues more effectively.

Example Scenario

Consider testing an e-commerce website. A scripted test might verify that a user can add an item to their cart and proceed to checkout. An exploratory test, on the other hand, might involve exploring different product categories, applying various filters, attempting to add out-of-stock items to the cart, or trying to manipulate the URL to bypass security checks.

Common Tools

Several tools can aid in exploratory testing:

• Session-Based Test Management (SBTM) tools: These tools, like TestRail, PractiTest, or XQual, help manage and document exploratory testing sessions. They provide features for chartering, note-taking, and reporting.
• Screen Recorders: Tools like OBS Studio (free and open-source), Camtasia, or Snagit can record testing sessions, capturing both the screen and audio commentary. This is invaluable for bug reporting and knowledge sharing.
• Bug Tracking Systems: Jira, Bugzilla, or Azure DevOps are essential for logging and tracking identified defects.
• Proxy Tools: Burp Suite or OWASP ZAP can be used to intercept and analyze web traffic, helping to identify security vulnerabilities.
• Mind Mapping Tools: Tools like XMind or FreeMind can help visualize the system under test and plan exploratory testing sessions.

Benefits of Exploratory Testing

• Early Bug Detection: Exploratory testing can uncover critical bugs early in the development cycle, reducing the cost of fixing them later.
• Improved Test Coverage: Exploratory testing can cover areas that might be missed by scripted tests, leading to more comprehensive test coverage.
• Enhanced Tester Skills: Exploratory testing encourages testers to develop their critical thinking, problem-solving, and communication skills.
• Increased Flexibility: Exploratory testing is highly adaptable to changing requirements and priorities.
• Better Understanding of the System: Exploratory testing helps testers gain a deeper understanding of the system under test, leading to more effective testing.

Limitations of Exploratory Testing

• Reproducibility: Bugs found during exploratory testing can be difficult to reproduce if the testing process is not well-documented.
• Subjectivity: Exploratory testing relies heavily on the tester's skills and knowledge, which can introduce subjectivity into the testing process.
• Measurability: It can be challenging to measure the effectiveness of exploratory testing compared to scripted testing.
• Dependency on Tester Skill: The success of exploratory testing is heavily dependent on the skills and experience of the tester.

In conclusion, exploratory testing is a valuable approach to software testing that complements scripted testing and can help to improve the quality, reliability, and security of software applications. By embracing the principles of learning, designing, and executing, and by utilizing appropriate tools and techniques, testers can effectively leverage exploratory testing to uncover hidden defects and deliver high-quality software.

Further reading

• Exploratory Testing 3.0
• Session-Based Test Management
• What is Exploratory Testing? A Complete Guide
• Exploratory Testing - Ministry of Testing