deno test doesn't use the specified compilerOptions.lib

[RobertAKARobin]

Tiny example repo:

https://github.com/RobertAKARobin/deno-test-err

It consists of:

// index.ts
export const div = document.createElement('div');

// index.test.ts
import { div } from './index.ts';
console.log(div);

// deno.jsonc
{
  "compilerOptions": {
    "lib": [
      "deno.ns",
      "dom"
    ]
  }
}

Steps to reproduce

1. Run deno bundle index.ts. Observe it compiles and completes successfully.
2. Run deno test index.test.ts

Expected result

deno test completes successfully, just like deno bundle.

Actual result

deno test fails with a fatal error:

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out (13ms)

error: Uncaught ReferenceError: document is not defined
export const div = document.createElement('div');
                   ^
    at file:///Users/robertthomas/Programming/web/deno-test-err/index.ts:1:20

deno test doesn't "know" about document, which indicates it is not respecting that the configuration file's compilerOptions.lib includes "dom".

If I add the --compat option...:

$ deno test --allow-all --config deno.jsonc --compat  --unstable --no-check index.test.ts 

...then the error changes:

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out (214ms)

error: Uncaught (in promise) SyntaxError: Cannot use import statement outside a module
  const [f, err] = core.evalContext(wrapper, filename);
                        ^
    at wrapSafe (https://deno.land/std@0.138.0/node/module.ts:1315:25)
    at Module._compile (https://deno.land/std@0.138.0/node/module.ts:251:29)
    at Object.Module._extensions..js (https://deno.land/std@0.138.0/node/module.ts:1334:10)
    at Module.load (https://deno.land/std@0.138.0/node/module.ts:239:34)
    at Function._load (https://deno.land/std@0.138.0/node/module.ts:558:14)
    at loadCjsModule ([deno:cli/compat/mod.rs:120:30]:3:22)

How can I write unit tests that include the DOM API?

[bartlomieju]

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out (13ms)

error: Uncaught ReferenceError: document is not defined
export const div = document.createElement('div');
                   ^
    at file:///Users/robertthomas/Programming/web/deno-test-err/index.ts:1:20

This is an actual runtime error and not TypeScript error. If you configure compilerOptions and pass "dom" it tells built-in TypeScript compiler that these types are available but it doesn't actually make document available in Deno, you would have to polyfill it yourself.

[RobertAKARobin]

Thanks @dsherret . Is there a workaround? It would be nice if I could unit test front-end code without needing to import a vendor library.

[bartlomieju]

@RobertAKARobin see https://deno.land/manual/jsx_dom/linkedom#using-linkedom-with-deno

[bartlomieju]

@RobertAKARobin FYI I opened denoland/docs#103 to improve our documentation on this topic.