Book: SE@Google Ch 11: Testing Overview

[jayasting98]

Book: SE@Google Chapter: 11 - Testing Overview

Summary:

• Benefits of Automated Testing
  • Less Debugging
  • Increased confidence in changes
  • Improved documentation of intended behaviour
  • Simpler reviews because less time spent by reviewer verifying correctness
  • Thoughtful design because code that is difficult to test is likely to not be designed well
  • Fast, high-quality releases because automated tests can be run quickly
• Test Size vs Test Scope
  • Test size describes the resources required to run a test
  • Test scope describes the specific code paths that are being verified
  • They are independent
  • It is possible to have small-sized, medium-scoped tests
  • It is possible to have medium-sized, narrow-scoped tests
• Test Size
  • Small: Test must run in one process
  • Medium: Test must run in one machine
  • Large: Test can run anywhere
  • Larger tests are slower, nondeterministic, and flaky
  • Prefer to write smaller tests
  • Test size can be enforced by tools
  • Tests can be made to fail if they are tagged as small but they block on I/O or make a network connection
• Test Scope
  • Narrow-scoped/unit: small, focused code, like an individual class, or an individual method
  • Medium-scoped/integration: verifies interactions between a small number of components
  • Large-scoped/functional/end-to-end/system: validates interactions between a several distinct components
  • Prefer to write more narrow-scoped tests
• Code coverage
  • Code coverage isn't everything
  • Beyoncé rule: If you liked it, then you shoulda put a test on it
  • Test whatever you don't want to break
• The Pitfalls of a Large Test Suite
  • There will be more brittle tests, which make teams avoid refactoring
  • Slow
  • Blocks productivity
  • Engineers will start working around tests
  • Some may skip them
• Changing testing culture in organizations takes time
• Automated testing cannot be used for everything
  • Quality of search results
  • Quality of audio/video
  • Security vulnerabilities

Relevance:

• We used to use a mainly medium-sized integration testing in the TEAMMATES back-end
• In hindsight, testing seems very slow
• We have only started introducing small-sized unit testing, which seems to be the way to go