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/* eslint no-shadow: 0 */
const test = require("tap").test;const ss = require("../");
function rnd(x) {    return Math.round(x * 1000) / 1000;}
test("sample covariance", function (t) {    t.test("can get perfect negative covariance", function (t) {        const x = [1, 2, 3, 4, 5, 6];        const y = [6, 5, 4, 3, 2, 1];        t.equal(rnd(ss.sampleCovariance(x, y)), -3.5);        t.end();    });
    t.test("covariance of something with itself is its variance", function (t) {        const x = [1, 2, 3, 4, 5, 6];        t.equal(rnd(ss.sampleCovariance(x, x)), 3.5);        t.end();    });
    t.test(        "covariance is zero for something with no correlation",        function (t) {            const x = [1, 2, 3, 4, 5, 6];            const y = [1, 1, 2, 2, 1, 1];            t.equal(rnd(ss.sampleCovariance(x, y)), 0);            t.end();        }    );
    t.test("unequal-length corner case", function (t) {        t.throws(function () {            ss.sampleCovariance([1], []);        });        t.end();    });
    t.test("zero-length corner case", function (t) {        t.throws(function () {            ss.sampleCovariance([], []);        });        t.end();    });    t.end();});