Bun's test runner supports Jest-style snapshot testing via .toMatchSnapshot().
snap.test.ts
import { test, expect } from "bun:test";
test("snapshot", () => {
expect({ foo: "bar" }).toMatchSnapshot();
});
The first time this test is executed, Bun will write a snapshot file to disk in a directory called __snapshots__ that lives alongside the test file.
test
├── __snapshots__
│ └── snap.test.ts.snap
└── snap.test.ts
To regenerate snapshots, use the --update-snapshots flag.
bun test --update-snapshotsbun test v1.x (9c68abdb)
test/snap.test.ts:
✓ snapshot [0.86ms]
1 pass
0 fail
snapshots: +1 added # the snapshot was regenerated
1 expect() calls
Ran 1 tests across 1 files. [102.00ms]See Docs > Test Runner > Snapshots for complete documentation on snapshots with the Bun test runner.