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Test Driven Development

by Srinesh Nisala (Senior Software Engineer @ iLabs)

Pre-requisites​

Project structure​

  • Explain how to run the application using IDE & Gradle
# with gradle
gradle run

# with gradle wrapper
./gradlew run
  • Explain how to run tests using IDE & Gradle
# with gradle
gradle test

# with gradle wrapper
./gradlew test

Basics of JUnit​

  • Create a simple test to print hello world (check the output in the debug console tab)

  • Introduce beforeEach and afterEach annotations

Exercise 1​

  • Create a Calculator class and add addition method
  • Show how to use IDE features to quickly create a test class
  • Tryout the addition method manually
  • Create a unit test to test the addition method

Exercise 2​

  • Create a test case for subtraction method
  • Use IDE features to generate the method signature
  • Implement the subtraction method

What is TDD?​

Test-Driven Development (TDD) is a Software development method in which you write Automation Tests before the actual development process starts

Red-Green-Refactor:

  • Focus on testing behaviors (requirements) rather than implementation details.
  • Write minimal code to pass tests ("green"),
  • Refactor without adding new tests.

TDD Best Practices​

  • Reduce mocking and stubbing
  • Avoid testing private/internal code; focus on public interfaces
  • Avoid Over-Testing

More on TDD​