jasmine-float-equals

jasmine-float-equals is a custom matcher for Jasmine deep comparing two objects while taking into account a tolerance for float comparison.

It can compare floats of type number but also floats that are embedded in a string, alone (ex: '10.01') or within a text (ex: 'My 1st is 10.01 and my second is 25.1').

Usage

Install the package :

npm install --save-dev jasmine-float-equals

Import the package before your tests and use the toEqualWithFloatTolerance(expected: any, epsilon: number, handleStringEmbeddedFloats: boolean) matcher.

• epsilon: the maximum difference allowed between two floats
• handleStringEnbeddedFloats (false by default): whether to also compare with a tolerance floats that are embedded in string

import 'jasmine-float-equals';

describe('my suit', function() {
    it('should pass with tolerance', function() {
        const expected = {
            hello: 10,
            world: {
                foo: 25
            }
        };
        const actual = {
            hello: 10.00001,
            world: {
                foo: 25.00005
            }
        };
        
        expect(actual).toEqualWithFloatTolerance(expected, 10e-6); // pass
        expect(actual).toEqualWithFloatTolerance(expected, 10e-7); // DON'T PASS
    });
    
    it('should pass with tolerance when embedded inside a string', function() {
        const expected = 'The result is 10.00001 units and 42.00001 subunits';
        const actual = 'The result is 10.00002 units and 42.00002 subunits';
        expect(actual).toEqualWithFloatTolerance(expected, 10e-6, true); // pass

        expect('10.00001').toEqualWithFloatTolerance('10.00002', 10e-6, true) // pass
    });
});

If you need to register the matcher at a given time, you can use the registerEqualWithFloatToleranceMatcher function.

import { registerEqualWithFloatToleranceMatcher } from 'jasmine-float-equals';

// at my specific time that I need it
registerEqualWithFloatToleranceMatcher();

This will register the matcher in a beforeAll block.

If you need to, you can also manually register the matcher to Jasmine using :

import { toEqualWithFloatToleranceMatcher } from 'jasmine-float-equals';


beforeAll(function () {
    jasmine.addMatchers({
        toEqualWithFloatTolerance: toEqualWithFloatToleranceMatcher
    });
});

Or execute the function manually:

let floatsAreEqual: boolean = toEqualWithFloatTolerance().compare(25, 25.00001, 10e-6).pass;

Credits

Crafted with ❤️ by Bastien MARSAUD.