Use .toBeEven when checking if a value is an even Number

import {
  defineExpect,
  not,
  test,
  toBeEven,
} from "https://deno.land/x/unitest@$VERSION/mod.ts";

const expect = defineExpect({
  matcherMap: {
    toBeEven,
  },
  modifierMap: {
    not,
  },
});

test("passes when value is an even number", () => {
  expect(2).toBeEven();
  expect(1).not.toBeEven();
  expect(NaN).not.toBeEven();
});