Testing Code

Terminology

• Test Fixture - A fixed state of a set of objects used as a baseline for running tests. There should be a well known and fixed environment in which tests are run so that the results are repeatable.
• Unit Tests / Unit Testing - Code written to test code uder test
  • Designed to test specific sections of code
  • Ideally code coverage is maybe 70-80%
  • Should be small and fast
  • No external dependencies
    • No databases or spring components
• Integration Tests - Designed to test behaviors between objecrts and parts of the overall system
  • Much larger scope
  • Can include the Spring Context, databases, and message brokers
  • Much slower than unit tests
• Functional Tests - Testing a running application
  • Likely deployed in a test env
  • Functional touch points are tested
• Test Driven Development - Write Tests first, which of course fail, then code to 'fix' it
• BDD - Specifies that tests of any unit of software should be specified in terms of desired behavior of the unit
  • Often implemented with DSLs to create natural language tests
  • JBehave, Cucumber, Spock
• Mock - A fake implementation of a class used for testing. Like a test Double.
• Spy - A partial mock, allowing you to override select methods of a real class.
  • Generally Mocking is more popular than Spying

Testing Goals

• Generally you want the majority of tests to be unit tests.
• Bringing up the Spring Context makes your test exponentially slower
• Try to test specific business logic in unit tests
• Use integration tests to test interactions
• Think of a pyramid. Base is unit tests, middle is integration, top is functional tests

Test Scope Dependencies

• Using spring-boot-starter-test will load the following:
  • JUnit - the de-facto standard for unit testing
  • Spring Test and Spring Boot Test - Utilites and integration test support for Spring Boot applications
  • AssertJ - fluent assertion library
  • Hamcrest - A library of matcher objects
  • Mockito - A Java mocking framework
  • JSONassert - An assertion library for JSON
  • JSONPath - XPath for JSON

JUnit Annotations

Spring Boot Annotations