A Jasmine matcher for comparing objects containing floats with a tolerance
npm install jasmine-float-equalsjasmine-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').
Install the package :
``bash`
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 floatshandleStringEnbeddedFloats
* (false by default): whether to also compare with a tolerance floats that are embedded in string
`ts
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.`ts
import { registerEqualWithFloatToleranceMatcher } from 'jasmine-float-equals';
// at my specific time that I need it
registerEqualWithFloatToleranceMatcher();
`
This will register the matcher in a block.
If you need to, you can also manually register the matcher to Jasmine using :
`ts
import { toEqualWithFloatToleranceMatcher } from 'jasmine-float-equals';
beforeAll(function () {
jasmine.addMatchers({
toEqualWithFloatTolerance: toEqualWithFloatToleranceMatcher
});
});
`
Or execute the function manually:
`ts``
let floatsAreEqual: boolean = toEqualWithFloatTolerance().compare(25, 25.00001, 10e-6).pass;