mongo/jstests/concurrency/fsm_selftests.js

/*
 * This file tests the FSM test framework.
 */

import {fsm} from "jstests/concurrency/fsm_libs/fsm.js";

(function () {
    let getWeightedRandomChoice = fsm._getWeightedRandomChoice;

    let doc = {a: 0.25, b: 0.5, c: 0.25};

    // NOTE: getWeightedRandomChoice calls assert internally, so it will print stack traces
    // when assert.throws executes
    assert.throws(
        function () {
            getWeightedRandomChoice(doc, -1);
        },
        [],
        "should reject negative values",
    );
    assert.throws(
        function () {
            getWeightedRandomChoice(doc, 1);
        },
        [],
        "should reject values == 1",
    );
    assert.throws(
        function () {
            getWeightedRandomChoice(doc, 2);
        },
        [],
        "should reject values > 1",
    );

    assert.throws(
        function () {
            getWeightedRandomChoice({}, 0.0);
        },
        [],
        "cannot choose from zero states",
    );
    assert.throws(
        function () {
            getWeightedRandomChoice({}, 0.5);
        },
        [],
        "cannot choose from zero states",
    );
    assert.throws(
        function () {
            getWeightedRandomChoice({}, 0.99);
        },
        [],
        "cannot choose from zero states",
    );

    assert.eq("a", getWeightedRandomChoice(doc, 0.0), "0");
    assert.eq("a", getWeightedRandomChoice(doc, 0.24), "1");
    assert.eq("b", getWeightedRandomChoice(doc, 0.25), "2");
    assert.eq("b", getWeightedRandomChoice(doc, 0.5), "3");
    assert.eq("b", getWeightedRandomChoice(doc, 0.74), "4");
    assert.eq("c", getWeightedRandomChoice(doc, 0.75), "5");
    assert.eq("c", getWeightedRandomChoice(doc, 0.99), "6");
})();