This plugin for QUnit adds close and notClose assertion methods to test that a number is approximately equal (or not) to an expected number, within a given tolerance.

assert.close(actual, expected, maxDifference, message);
assert.notClose(actual, expected, minDifference, message);

Where:

• maxDifference: the maximum inclusive difference allowed (tolerance) between the actual and expected numbers
• minDifference: the minimum exclusive difference allowed (tolerance) between the actual and expected numbers
• actual, expected, message: The usual

test('Example unit test', function(assert) {
  assert.close(3.141, Math.PI, 0.001);
  assert.notClose(3.1, Math.PI, 0.001);
}

For more examples, refer to the unit tests.