JSTests/modules/resources/assert.js

export function shouldBe(actual, expected) {
    if (actual !== expected)
        throw new Error(`bad value: ${String(actual)}`);
}

export function shouldNotBe(actual, expected) {
    if (actual === expected)
        throw new Error(`bad value: ${String(actual)}`);
}

export function shouldThrow(func, errorMessage) {
    var errorThrown = false;
    var error = null;
    try {
        func();
    } catch (e) {
        errorThrown = true;
        error = e;
    }
    if (!errorThrown)
        throw new Error('not thrown');
    if (String(error) !== errorMessage)
        throw new Error(`bad error: ${String(error)}`);
}

export function shouldNotThrow(func) {
    func();
}