const assert = require('assert');

function add(a, b) {
  return a + b;
}

assert.strictEqual(add(2, 3), 5);
assert.strictEqual(add(-1, 1), 0);

try {
  assert.strictEqual(add(2, 2), 5);
} catch (err) {
  console.log(err.name);    // AssertionError
  console.log(err.message); // Expected values to be strictly equal
}