typecellos Testing
In most cases, once a feature, bug fix, or other modification has been written, it will need to have tests added, or existing tests updated.
Test File Locations
Unit Tests
/tests/src/unit: Contains the bulk of unit tests, mainly relating to interoperability between BlockNote's JSON format and HTML/Markdown. Also includes some miscellaneous tests, like React rendering, selection handling, and NextJS integration.
/packages/core/src/api: Contains mainly tests for getting, inserting, updating, and removing blocks, etc, under /blockManipulation/commands. Also includes tests for intermediary functionality between BlockNote and the underlying TipTap editor, like converting between blocks & nodes, or setting editor event handlers.
/packages/xl-*: Contain tests for functionality included in a given xl-* package.
Colocated Browser Unit Tests
packages/*/src/**/*.browser.test.{ts,tsx}: Unit tests for browser-only implementations (e.g. canvas or DOM-dependent code) live next to the code they test, with a .browser.test suffix. They run as part of the browser suite in Docker (the tests package's browser config includes them); the packages' own node-mode vitest configs exclude them. Use this when the unit under test genuinely needs a real browser — everything else should be a plain node unit test.
End-to-End Tests
tests/src/end-to-end: Tests that need a real browser and span multiple packages go here — chiefly tests which interact with the editor UI or simulate user interaction, but also browser integration tests that exercise complete flows without interaction (e.g. exporting a full document, static rendering). New subdirectories can be added if the functionality being tested is not covered by any of the existing ones. Important note about existing E2E tests - many are written poorly and should only loosely be used as reference. We want to avoid abstraction layers and waitForTimeout as much as possible.
When & How to Add Tests
In general, we expect a change in code to result in failing test cases. If this does not happen, tests should be added and checked to ensure they pass with the code changes while failing without them.
However, this may not be true when adding edge case handling or a new feature, where existing tests may all continue to pass. In this case, tests should be added as necessary to cover all of the new functionality. We should still ensure that the new tests pass with the new code changes while failing without them.
We want to avoid adding end-to-end tests where it's possible to use unit tests instead.
Don't use jsdom (@vitest-environment jsdom) in new tests. It's a murky middle ground — document exists but rendering doesn't — which makes browser-capability checks pass while the capability itself is broken. Use the default node environment with pluggable seams for logic, and the browser suite (tests/src/end-to-end, vitest browser mode in Docker) for anything that needs real rendering.
Running & Updating Tests
Unit Tests
Unit tests can be run from the root directory using vp run test, which will run all of them across all directories. A specific test file may be targeted by appending its name, i.e. vp run test fileName. Individual tests in a file may be disabled using skip, i.e. it.skip("Test name", ...) (remember to revert this once all tests pass).
Updating tests can be done by adding the -u argument, i.e. vp run test -u. All of the other things you can do to scope which tests to target still apply.
End-to-End Tests
End-to-end tests run in vitest browser mode (chromium, firefox and webkit) inside a Docker container, so screenshot baselines are identical locally and on CI. Run them from the repository root:
bash tests/docker-run.sh -e CI=1 -- --run [filters]
Never run the browser suite natively (vp test -c vite.config.browser.ts outside the container) — not even "just one file". Two failure modes, both silent: the screenshot matcher seeds a new -darwin/-win32 baseline for every screenshot test that has none (passing without comparing anything, and littering the tree with hundreds of unvetted PNGs — these are gitignored as a backstop, and only -linux baselines are tracked), and several suites genuinely behave differently outside Linux (e.g. caret placement is font-metric-dependent, so platform-shared JSON snapshots mismatch). If Docker isn't running, notify the user to launch it instead of falling back to a native run.
A specific test file may be targeted by appending (part of) its name as a filter. A single browser may be targeted with --project "e2e (chromium)". Individual tests in a file may be disabled using skip, i.e. test.skip("Test name", ...) (remember to revert this once all tests pass).
Screenshot baselines can be regenerated with --update=true (as e2e:updateSnaps does). Always attach the value: vitest declares the flag as -u, --update [type] (it also accepts new/all/none), so a bare -u before a filter swallows the filter as its value and silently runs the whole suite in update mode. --update=true cannot, so filters stay filters in any position. Note that -u only rewrites baselines whose comparison fails — a small intended change (e.g. a short text edit) that fits inside the suite's 2% pixel tolerance leaves the baseline stale while the test passes. To force a fresh capture, delete the baseline file first. Baselines are per-browser (<name>-<browser>-linux.png); after regenerating, always inspect the images before committing them.
When testing a visual change, prefer writing screenshots to verify that the change is working as expected.
Screenshots of tall content: browser-suite tests run inside a tester iframe sized to the browser window (1280x720), and element screenshots only contain what the iframe actually paints — anything below its fold captures as blank white, silently. Growing the iframe with page.viewport() alone doesn't fix this at full resolution: the harness scales the iframe down to fit the window, shrinking the resulting baseline (static.test.tsx accepts that trade-off). For full-resolution captures use screenshotFull (tests/src/utils/screenshotFull.ts), which grows the iframe past the content and neutralizes the harness's scale transform during the capture — the same mechanism upstream Vitest adopted in vitest-dev/vitest#9745 (milestone 5.0.0; the util can be deleted once vite-plus ships it). Always eyeball newly generated baselines for truncation.