vl - unit testing

Introduction to Unit Testing

• Overview:

  • One of the most important yet often overlooked topics in software development.

  • Requires a different mindset from typical programming practices.

  • Increasing emphasis in organizations on unit testing.

Definition of Unit Testing

• What is Unit Testing?

  • A method to ensure that code functions as intended.

  • Involves testing small, specific segments of code.

  • Differentiation from previous schooling methods, where code was tested manually by running the entire application.

  • Traditional method is slow, as it relies on having all components functioning.

  • Efficiency of Unit Testing:

  • Allows testing of isolated functions without needing to deploy the entire application.

Unit Testing Process

• Creating Unit Tests:

  • Aim for specificity and granularity in tests.

  • Focus on specific classes and functions rather than the entire application.

  • Example:

  • If having a calculator class with an addition function, the unit test should focus solely on that addition function.

Clarifications on Unit Testing Scope

• Limitations of Unit Testing:

  • Not for validating user input (despite the use of assertions).

  • Execution Timing:

  • Unit tests are run at compile time, not runtime.

Best Practices in Unit Testing

• New Code and Corresponding Tests:

  • When writing new code, create corresponding unit tests to verify correct functionality.

  • Existing Tests:

  • Run the entire suite of existing tests after introducing new code to ensure nothing is broken.

  • Impact on Code Quality:

  • Increases confidence in code integrity and guarantees previous functionalities remain intact.

Unit Testing Libraries

• Available Libraries:

  • Popular libraries for unit testing include:

  • Jasmine

  • Mocha

  • Karma

  • Acknowledgement of their existence is important; further learning about these libraries is encouraged.

Structure of Writing Unit Tests

• Basic Structure:

  • Begin with writing a test suite to encapsulate all tests.

  • A variable pointing to a function containing sub-functions for individual tests.

  • Example naming convention: use the prefix "test" for all test functions (e.g., testSomething).

• Assertion Use:

  • Assertions verify that actual outcomes match expectations.

  • Example of Assertion:

  • testOneEqualsOne(): Asserts that one is equal to one, showcasing trivial verification.

  • For a calculator class instance, testing add(0, 1) should yield an outcome that equals one, confirming functional correctness.

• Types of Assertions Found:

  • Assert that something is true.

  • Assert that something is false.

  • Assert equality of results.

  • Assert inequality of results.

  • Assertions generally follow similar formats across libraries.

Considerations for Effective Testing

• Performance of Tests:

  • Tests should be swift and not involve database connections or remote website calls.

  • Aim to test logical processes rather than I/O operations like database access.

  • Regular practice and improvement in unit testing skills over time.

Workflow of Unit Testing

• Before Code Submission:

  • Run all unit tests prior to integrating code into version control (e.g., GitHub).

  • Fix broken tests before pushing code changes to ensure stability in the shared codebase.

Conclusion

• Unit testing is a crucial practice for ensuring code quality, and efficient testing can greatly enhance software development and maintenance.