swdes/diamond-kata

JavaScript

TDD

What

Write tests before the code

Why

full code coverage
KISS
modularity / architecture
document
easy to refactor
ease collaboration (no fear to break something)
less dependencies / useless code
less bug fix...
clear interfaces

But, on the other hand

you have to maintain your tests
some tests are hard to write: mocks, strong integration...
difficult with legacy code
don't push the tests to far... as everything, consume with moderation

How

for (const spec in specs) {
    1. RED: Create a test and check it fails
    2. GREEN: Code the spec so test is successfull
    3. REFACTO: Refactor if needed
}

Diamand Kata

Print a A diamond
Print a B diamond
Print a C diamond
Print a D diamond

printDiamond("D") should produce a string containing

    A
   B B
  C   C
 D     D
  C   C 
   B B
    A