Test Process, Episode 22

Timing:

• 00:00-00:45 intro
• 00:45-03:45 overview
• 03:45-10:45 astronomy lesson: the great galaxy debate
• 10:45-53:10 simple techniques
  • 16:40 stairstep tests
  • 24:40 assert first
  • 31:40 triangulation
  • 47:05 one to many
• 53:10-1:10:10 refactoring tests
  • 56:25 the two disks
• 1:10:10-1:15:10 tests come first
• 1:15:10-1:18:00 heresy
• 1:18:00-1:20:30 summary
• 1:20:30-1:22:50 ending credits

Concepts:

• “Fake it ’til you make it” - make a test case pass by faking it, e.g., just returning 0 to test an edge case.
• Stairstep tests - tests whose sole purpose is to enable you to write the next step in sequence (usually delete when no longer needed)
• Assert first - write test backwards, starting with the assert; i.e., write the assert, then iteratively fix one error at a time by adding only the code needed to make that one error go away.
• Triangulation - adding a second specific test that will force you to modify the code you are currently testing to be more general (two tests + code being testeed = triangle); may lead to extracting an abstract class.
• One to many -
• Trap door function
• Golden rule of writing tests
• Test behavior, not APIs.
• Four rules of simple design: