Support callable instances

[bojavou]

Purpose (TL;DR) - mandatory

Support callable instances
Closes #2516

Background (Problem in detail)

Enables testing constructors that return functions. #2516 has further description.

Solution - optional

The constructor return value seems to be checked in proxy-invoke.js. This expands the typeof check to include functions.

if (typeof returnValue !== "object" && typeof returnValue !== "function") {
  returnValue = thisValue;
}

This works for my code in a local patched version. Tests are included to verify.

How to verify - mandatory

1. Check out this branch
2. npm install
3. npm test

You can verify manually by running this code from the checkout root. Output should be true.

import sinon from './pkg/sinon-esm.js'
function CallableInstance () { return () => {} }
const SpiedCallableInstance = sinon.spy(CallableInstance)
const callable = new SpiedCallableInstance()
console.log(typeof callable === 'function')

$ nano test.js
true

Checklist for author

• npm run lint passes
• References to standard library functions are cached.

[codecov]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (05f05ac) 96.00% compared to head (da60bbf) 96.00%.

❗ Current head da60bbf differs from pull request most recent head be30ce0. Consider uploading reports for the commit be30ce0 to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2517   +/-   ##
=======================================
  Coverage   96.00%   96.00%           
=======================================
  Files          40       40           
  Lines        1900     1900           
=======================================
  Hits         1824     1824           
  Misses         76       76           

Flag	Coverage Δ
unit	96.00% <100.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
lib/sinon/proxy-invoke.js	97.91% <100.00%> (ø)

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[fatso83]

Thanks, this seems nice :)

[bojavou]

Thank you! I'll be glad to switch back to mainline.