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Software Testing, TDD, and BDD

Why Test?​

Testing ensures software quality and reliability by detecting errors early in the development lifecycle.

Causes of Errors:​

  • Miscommunication of requirements
  • Poorly understood features
  • Human errors in logic or syntax
  • Integration conflicts

Types of Software Testing​

1. Unit Testing​

  • Tests individual components or units of code (e.g., a function or method).
  • Focuses on internal logic.

2. Integration Testing​

  • Tests the interaction between units or modules.
  • Helps ensure that components work together properly.

3. Regression Testing​

  • Ensures that new code does not break existing functionality.
  • Important when code is refactored or updated.

4. Use Case Testing​

  • Tests if the application behaves correctly based on user scenarios or workflows.

5. User Acceptance Testing (UAT)​

  • Confirms whether the system meets the requirements of the end user.
  • Includes subjective and objective test cases.
  • Typically the final phase before deployment.

6. Performance Testing​

  • Assesses how a system performs under load, volume, stress, and endurance.
    • Load testing
      • Volume testing: Mainly focuses on databases
      • Endurance testing: Testing the sustainability of the system under continued load
    • Stress testing
      • Analyze post-crash reports to define the behavior of the application after failure.
      • Ensure that the system does not compromise the security of sensitive data after the failure.

UAT Deliverables​

  • Test Plan: Strategy, criteria, and roles
  • Test Cases: Step-by-step instructions
  • Test Log: Record of executed tests and results
  • User Sign-Off: Final approval confirming the product meets expectations

How to Conduct UAT – AltexSoft

Why Automate Unit Testing?​

  • Saves time on repeated tests
  • Ensures tests are run consistently
  • Enables quick bug detection and fixes
  • Facilitates continuous integration

How It Works​

  1. Determine the expected output
  2. Compute the actual output
  3. Compare them → Pass or Fail

Test-Driven Development (TDD)​

"Write tests before you write your code.”

TDD Cycle:​

  1. Write a failing test
  2. Write the minimal code to pass the test
  3. Refactor the code
  4. Repeat

Benefits:​

  • Leads to modular, reusable code
  • Encourages thinking from the user’s perspective
  • Reduces bugs and improves test coverage

Behavior-Driven Development (BDD)​

BDD is a refinement of TDD. It focuses on natural language descriptions of software behavior.

Structure:​

  • GIVEN some initial context
  • WHEN an event occurs
  • THEN ensure some outcome

Example:​

GIVEN: User is on the Google homepage
WHEN: User searches for “BDD”
THEN: Results for “BDD” are displayed

Advantages:​

  • Improves communication across stakeholders
  • Ensures clarity of requirements
  • Makes test automation easier

Reflection Questions​

  • List 3 benefits of rigorous testing.
  • Identify testing methods that can be automated.
  • When should testing be done in the development cycle?
  • What is the primary goal of integration testing?
  • Which testing ensures older features still work after new ones are added?
  • What is black-box testing?

Summary​

  • Testing is essential for delivering high-quality, bug-free software.
  • TDD ensures your code is written with testing in mind.
  • BDD helps bridge the gap between technical and non-technical team members.
  • Automation frameworks make testing scalable and reliable.

Disclaimer: Generative AI was used in part to generate these lecture notes.