Write your own TDD lib in CodeWars and Codingame

Codewars and Codinggame can be great tools for programming deliberate practice.

However the katas test are already written for.

If it can help quickly learn new stuff, it can be frustrating for people who wants the practice Test-Driven Development not to write their own tests.

Did you know you can write you own testing library inside the kata you are practicing?

The smallest testing library consists in assertEquals(actual,expected).

Additional stuff is just sugar.

Here is an example of this kind of testing library in a random Codewars Typescript Kata.

Of course you can use any language you want if it support standard error output.

export function humanReadable(seconds:number):string {
// TODO
let result='00:00:00';
return result;
}



// After the function to implement in the kata you can run any code you want
// So we write our testing library ...
function assertEquals(
  actual:any, expected:any,
  description:string = `Expected "${actual}" to equal "${expected}"`){

if(actual === expected){
  // Codewars allows you to log anything you want using standard error output
    console.error(`✅ : ${description}`)
  } else {
    console.error(`❌ : ${description}`)
  }
}


// ... and then our own assertions
assertEquals(humanReadable(0),'00:00:00')
assertEquals(humanRefadable(5),'00:00:05')