uvu supports snapshot testing, though it works a little differently to how it works with Jest. uvu snapshot testing was deliberately set up this way. With Jest, for example, when the stored snapshot differs from the test result, the developer can hit a key automatically to update the stored snapshot to match the current test result. It is all too easy to accept the result without checking what the actual difference is. As such, this potentially becomes an easy way to introduce regressions. To help mitigate that risk, with uvu, you have to update snapshots manually. You can add a snapshot to an uvu test using assert.snapshot.