import { assertThrowsAsync } from "https://dotland.deno.dev/x/dejs@0.9.3/vendor/https/deno.land/std/testing/asserts.ts";
Executes a function which returns a promise, expecting it to throw or reject. If it does not, then it throws. An error class and a string that should be included in the error message can also be asserted.
Parameters
fn: () => Promise<T>