Cover the parts of the library nothing reached

[enyo]

Stacked on #2359, which added the measurement. This closes the gaps it exposed.

	before	after
Statements	72.26%	79.84%
Branches	68.70%	77.09%
Functions	80.47%	92.85%
Tests	191	252

emitter.js reaches 100% on all three.

The largest hole was drag and drop

The existing suite calls dropzone.drop() directly, which bypasses the listeners the constructor binds to the element. Every handler — dragstart, dragenter, dragover, dragleave, drop, dragend and the click forwarding, the whole point of the library — ran in no test at all.

They are covered now through real DOM events, including the two subtleties:

• a drag carrying anything other than files is left alone, so the library does not interfere with other drag-and-drop on the page
• dropEffect is set to copy unless effectAllowed says otherwise, which is what makes dragging out of Chrome's download bar work, and the read is wrapped because IE 11 threw on it

I checked these have teeth rather than passing vacuously: making containsFiles always return true fails four of them.

Also covered

paste, the transport failures (ontimeout, onerror, progress forwarding — only the success path had tests), displayExistingFile, the fallback form, the removal confirmations, renameFilename, handleFiles and Dropzone.discover.

Three tests pin behaviour that is wrong

Each points at the roadmap entry that will change it, so the fix has to be deliberate rather than accidental:

• paste does not emit addedfiles, while drop() has since 6.2 and the hidden input always has
• displayExistingFile does not count towards maxFiles — Fix maxFiles issue when added files from server #2003, where the documented workaround is why it cannot be fixed in a patch
• new Dropzone(el, { forceFallback: true }) returns the fallback input, not a Dropzone. fallback() ends with return this.element.appendChild(...), and a constructor returning an object overrides this

A trap in the test suite itself

The emitter's tests sat behind return describe(...) — a CoffeeScript conversion artefact. The return ends the enclosing callback, so anything appended after it is never registered. That is exactly what happened here: the first four tests I added reported as passing while not running at all, and only counting them caught it.

There are eleven more in all.js. Removing every return there leaves the count at 252 either way, so none of them hide anything today — but they are the same trap, and they are gone.

End-to-end

Better than I expected going in: the suite already drives a real drop through a real DataTransfer against the built dropzone-min.js, so drag-and-drop, the standalone bundle and real HTTP were all covered.

The actual gap was failure — the test server only ever answered 200, so no rejected upload could be reached. It can now, and a new spec drives a real 500 through to the message rendered in the preview. That also pins something worth knowing: because the body is application/json with an error key, the user sees the server's own message, not dictResponseError.

Still worth adding later, in rough order of value: a chunked upload end to end (the S3 spec covers multipart, not Dropzone's own chunking), and maxFiles rejection.

What is deliberately still uncovered

dropzone.js sits at 77.42%, and the bulk of the remainder is one block: ExifRestore, roughly a hundred lines of base64 segment manipulation at lines 2026–2179. It is module-private, so testing it means either exporting it — which puts it in the public API for tests alone — or reaching it through createThumbnail with a real JPEG and canvas.

Worth doing, and worth saying where: the roadmap calls #2001, the EXIF rewrite, the highest-risk pull request in the backlog, whose author says they could not test it. That rewrite is exactly when this safety net is needed, so it belongs with it rather than here.

The rest is the jQuery plugin (needs jQuery present at module load), __guard__/__guardMethod__ and the IE 11 branches — all on the 7.0 list for deletion.

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	79.42%	880 / 1108
🔵	Statements	79.84%	927 / 1161
🔵	Functions	92.85%	195 / 210
🔵	Branches	77.09%	505 / 655

File Coverage

No changed files found.

Generated in workflow #86 for commit 74931ec by the Vitest Coverage Report Action