Add jest or similar test runner

[gdegas]

Hi, would you be open to adding jest as a test runner and being able to make a .test.js file and have multiple test suites. I find that the single test runner in indes.js works but I would like to have multiple test assertions for multiple unit/functions. In the current scenario I have to run each function that i want to test within the single run function. Thoughts?

[gdegas]

I'm trying to do it on my own by adding a index.test.js file but I can't get jest to be configure to be able to use import syntax.

I keep getting error SyntaxError: Cannot use import statement outside a module

> aoc2022@1.0.0 test
> jest

 FAIL  src/day05/index.test.js
  ● Test suite failed to run

    Jest encountered an unexpected token

    Jest failed to parse a file. This happens e.g. when your code or its dependencies use non-standard JavaScript syntax, or when Jest is not configured to support such syntax.

    Out of the box Jest supports Babel, which will be used to transform your files into valid JS based on your Babel configuration.

    By default "node_modules" folder is ignored by transformers.

    Here's what you can do:
     • If you are trying to use ECMAScript Modules, see https://jestjs.io/docs/ecmascript-modules for how to enable it.
     • If you are trying to use TypeScript, see https://jestjs.io/docs/getting-started#using-typescript
     • To have some of your "node_modules" files transformed, you can specify a custom "transformIgnorePatterns" in your config.
     • If you need a custom transformation specify a "transform" option in your config.
     • If you simply want to mock your non-JS modules (e.g. binary assets) you can stub them out with the "moduleNameMapper" config option.

    You'll find more details and examples of these config options in the docs:
    https://jestjs.io/docs/configuration
    For information about custom transformations, see:
    https://jestjs.io/docs/code-transformation

    Details:

    /Users/gdegas/dev/personal/aoc2022/node_modules/aocrunner/lib/index.js:1
    ({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,jest){import fs from "fs";
                                                                                      ^^^^^^

    SyntaxError: Cannot use import statement outside a module

    > 1 | import run from "aocrunner"
        | ^
      2 |
      3 | export const foo = (inp) => inp + 1
      4 | // module.exports = { foo }

      at Runtime.createScriptFromCode (node_modules/jest-runtime/build/index.js:1449:14)
      at Object.<anonymous> (src/day05/index.js:1:1)
      at Object.<anonymous> (src/day05/index.test.js:1:1)

Test Suites: 1 failed, 1 total
Tests:       0 total
Snapshots:   0 total
Time:        0.36 s
Ran all test suites.

I used this stack overflow answer still no luck https://stackoverflow.com/a/64223627

[brahn]

Trying this template out for AOC 2023, and the following approach seems to be sufficient for running tests from the command line (which is not quite as slick as running from the aocrunner itself, and this will not run the test cases exercised by the start -- so lots of room for improvement here)

Note that I am using npm...

1. Install just by running npm install --save-dev jest @types/jest ts-jest.

2. Add the following stanza to package.json. Note that this approach assumes all tests are inside src/ with the extension .test.ts. You may prefer to do something different.

   "jest": {
     "roots": ["<rootDir>/src"],
     "testMatch": ["**/*.test.ts"],
     "transform": {"^.+\\.ts$": "ts-jest"},
     "moduleFileExtensions": ["ts", "tsx", "js", "jsx", "json", "node"],
     "moduleNameMapper": {"^(.*)\\.js$": "$1"}, 
   }

(That cryptic last piece about moduleNameMapper was needed to get jest to recognize imports with the .js extension.)

3. Add "test": "jest" to the scripts stanza of package.json.

4. Create test files wherever you like inside src/ with a .test.ts extension, e.g. src/day01/part1.test.ts:

   test("basic test example", () => {
     expect(1 + 1 == 2).toBe(true);
   });

5. Run tests with npm test.