Playground

The same runner the JavaScript panels use, with the assertion helper already defined. A browser cannot run bash, Docker, kubectl or Terraform, so this is JavaScript only -- good for the arithmetic parts of the job: cost estimates, capacity planning, policy checks.

Scratch

runs here

1
2
3
4
5
6
7
8
9
10
11
12
13const same = (a, b) => JSON.stringify(a) === JSON.stringify(b);
const test = (name, got, want) => console.log(
  (same(got, want) ? 'ok   ' : 'FAIL ') + name +
  (same(got, want) ? '' : `  got ${JSON.stringify(got)}, want ${JSON.stringify(want)}`)
);
// Never use === on a computed float. Money and percentages below are rounded first.
const close = (a, b, tol = 1e-9) => Math.abs(a - b) < tol;

// Try something. test(name, got, want) prints ok or FAIL.
const monthlyCost = (hourlyRate, hoursPerMonth) => hourlyRate * hoursPerMonth;

console.log('a t3.micro-ish rate for 730 hours =', monthlyCost(0.0104, 730));
test('a full month of a cheap instance is a few dollars', close(monthlyCost(0.0104, 730), 7.592), true);

Output

New writing, when it lands.