Black-box Testing

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Black Box Testing is a method of evaluating the functionality of a software application without knowledge of its internal code structure, implementation details, or internal paths. This approach can be applied to various levels of testing, including unit, integration, system, and acceptance testing.

Black Box Testing focuses on the input and output of a software application as determined by its specifications. During this process, a tester inputs data and observes the output generated by the system under test. This allows the tester to determine how the system handles expected and unexpected user actions and assess its response time, usability, and reliability.

Black Box Testing is also referred to as Requirement-based Testing, Specification-based Testing, Behavioral Testing, Opaque-box Testing, Closed-box Testing, or Eye-to-eye Testing.

Table of Contents

  1. Black-box test techniques characteristics
  2. Black Box Testing Types
  3. Black Box Testing Techniques
  4. Black Box Testing Tools
  5. Advantages of black box testing
  6. Disadvantages of black box testing
  7. Video Tutorial

Black-box test techniques characteristics

Characteristics common to Black Box Testing techniques include the following:

  • Test conditions, test cases, and test data are derived from a test basis that may include software requirements, specifications, use cases, and user stories.
  • Test cases can be used to identify any discrepancies between the requirements and their implementation, as well as deviations from the requirements.
  • Coverage is determined based on the items tested in the test basis and the technique applied to the test basis.

Black Box Testing Types

Black Box Testing can be applied to three main types of tests: 

  1. Functional
  2. Non-functional
  3. Regression testing.

Black Box Testing Techniques

The International Software Testing Qualifications Board (ISTQB) Syllabus describes five Black Box Testing techniques:

  1. Equivalence Partitioning 
  2. Boundary Value Analysis
  3. Decision Table Testing
  4. State Transition Testing
  5. Use Case Testing

Black Box Testing Tools

Black Box Testing can be performed manually or with the use of automation tools. For functional or regression testing, tools such as Selenium, Cypress, Playwright, and Appium can be utilized. Non-Functional testing can be performed with tools like JMeter and LoadRunner.

Advantages of Black Box Testing

Black Box Testing has the following benefits: 

  • Implementation, programming, and operating system knowledge are not necessary.
  • Tests are conducted from the perspective of the user or client.
  • It is effective at identifying ambiguity and contradictions in functional specifications.
  • Testing procedures can be unbiased as development and testing procedures are independent.
  • It is suitable for large and complex systems.
  • Defects are detected early on in the process.
  • Testers do not need to understand the code, making outsourcing a possibility.

Disadvantages of Black Box Testing

Black Box Testing has the following disadvantages:

  • The functional specification must be clear in order to create test cases.
  • Test coverage may be limited as complete coverage is only possible by examining the code.
  • Tests may be redundant and time-intensive.
  • Debugging is more time-consuming compared to white box test cases.