Testing and Refactoring sharing

  • Bi-weekly Tech Sharing


  • Experience
  • Testing
  • Refactoring
  • References


  • best thing learned this year

  • I’m proud that we have testing culture and code review

  • how I test my code before?

    • coding -> run program -> postman / repl -> verify by eye -> QA
  • how I test my code now?

    • coding -> add tests -> green -> refactoring -> coding -> repeat -> code review
  • hopefully I’ll benefit from TDD style sooner


  • raise a question: we’re relying on tests to guarantee code work as expected, who guarantees our tests are correct then?

    • short answer: we can only rely on simple tests
    • too simple to be wrong(ideal world)
  • testing proportion

  • testing helped on

    • building confidence
    • building solid(bug free) code as possible
    • gives me a button to click
      • “if you ever get that button, you’ll never want to lose it or work other way round so you wouldn’t have it.”
  • testing drives me to write simple code

    • I want class to be small
    • I want responsiblilty to be single/simple/clear
    • I want method to be short
    • I want interface to be well defined
    • I love good names
  • example of using let(private git repo pull request)

    • demo for independant tests
    • avoid mutable variable
    • discipline posed upon assignment/mutability
  • key points:

    • write simple code & test when possible
    • more unit tests
    • “write enough tests to be confident”


  • let’s put performance aside while coding & refactoring

  • let’s focus on clarity/simplicity/readability/maintainability, not performance

    • make it simple
    • make it easier to read/review
    • make it easier to change/maintain
  • How I do code refactoring?

    • clean up feature flags
    • check code coverage and make it up to 100%
    • remove code smell
    • simplify code
    • enjoy the tiny changes/improvements
    • enjoy the green dots
    • enjoy the red dots(it shows I didn’t fully understand my code)
    • remove unused/dead code(unused)
    • check with flog(rely on metric tools, not “feeling”)
    • choose a better name for variables/methods/class/file/moudles
    • simplify tests
    • I got better understanding of the code, and I can repeat the above process…
  • example of simplifying code(private git repo pull request)

  • The point is: “business complixity is the lower limit of system complixity”

    • so I want my code to be as simple/readable as possible
    • try functional thinking: e.g. use filter/map/reduce
    • ruby: Enumerable module is amazing
  • key points:

    • lean on tests, no tests, no refactoring
    • do your refactoring with small steps(highlighted in both “refactoring” and “99 bottles of OOP”)
    • refactoring is just pattern matching(focus on code smell) and follow the solution


At last

these are just my limited experience on testing & refactoring; I’m pretty sure I have a lot more to learn

I really want to learn from everyone about these two topics

pls correct me if I’m wrong. pls discuss with me if you’re interested~ Orz