Many assertion functions have specific parameters for the expected and actual values. Swap them, and your test will still have the same outcome (succeed/fail when it should) but the error messages will be confusing.

This rule raises an issue when the "expected" argument of an assertion function is a hard-coded value and the "actual" argument is not.

This rule currently supports Chai assertions.

Noncompliant Code Example

const assert = require('chai').assert;
const expect = require('chai').expect;
const should = require('chai').should();

it("inverts arguments", function() {
    assert.equal(42, aNumber); // Noncompliant
    expect(42).to.equal(aNumber); // Noncompliant
    should.fail(42, aNumber);  // Noncompliant
});

Compliant Solution

const assert = require('chai').assert;
const expect = require('chai').expect;
const should = require('chai').should();

it("inverts arguments", function() {
    assert.equal(aNumber, 42);
    expect(aNumber).to.equal(42);
    should.fail(aNumber, 42);
});