Performing Stackblitz Unit Testing with Power Assert as a Minimal Testing Framework

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Scenario

We have created a function that returns a quadrant given a center and x and y coordinates. We want to unit test it in Stackblitz using Node’s assert function as a minimal testing framework.

function quadrant(MC: MetaCoordinates): Quadrant {
  if (MC.x <= MC.c.x) {
    if (MC.y <= MC.c.y) {
      return 1;
    } else {
      return 2;
    }
  } else {
    if (MC.y <= c.y) {
      return 4;
    } else {
      return 3;
    }
  }
}

Approach

Since we want to use Typescript and Node’s assert we will install power-assert within our Stackblitz and import assert like this.

import assert from 'power-assert';

We can now run our tests.

const testData: TestInput[] = [
  { x: 99, y: 100, c, q: 1 },
  { x: 99, y: 99, c, q: 1 },
  { x: 100, y: 100, c, q: 1 },
  { x: 100, y: 99, c, q: 1 },
  { x: 99, y: 101, c, q: 2 },
  { x: 100, y: 101, c, q: 2 },
  { x: 101, y: 101, c, q: 3 },
  { x: 101, y: 99, c, q: 4 },
];

function test(i: TestInput): boolean {
  return quadrant(i) == i.q;
}

//assert(false, 'Test Failed');

testData.forEach((d) => {
  assert(test(d), 'fail message ...');
});

Demo

Typescript Power Assert Unit Tests - StackBlitz