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node:test: assertion failures inside async callback (done-style test) are ignored and test incorrectly passes #28501
Description
What version of Bun is running?
1.3.11-canary.1+9e93bfa1b
What platform is your computer?
Linux 5.10.0-12-amd64 x86_64 x86_64
What steps can reproduce the bug?
Description
When using callback-style tests (done) with node:test, assertion failures thrown inside asynchronous callbacks (e.g. setTimeout) are not captured by Bun's test runner. As a result, the test is reported as passing even though an assertion fails.
PoC
"use strict";
const { describe, test } = require("node:test");
const assert = require("node:assert");
describe("describe wrapper", () => {
test("callback test", (t, done) => {
setTimeout(() => {
assert.ok(false, "oh no an assert failed");
done();
});
});
});What is the expected behavior?
root@KContainer:~/51381# node --test b.test.cjs
▶ describe wrapper
✖ callback test (3.315869ms)
✖ describe wrapper (4.996912ms)
ℹ tests 1
ℹ suites 1
ℹ pass 0
ℹ fail 1
ℹ cancelled 0
ℹ skipped 0
ℹ todo 0
ℹ duration_ms 96.535574
✖ failing tests:
test at b.test.cjs:6:3
✖ callback test (3.315869ms)
AssertionError [ERR_ASSERTION]: oh no an assert failed
at Timeout._onTimeout (/51381/b.test.cjs:8:14)
at listOnTimeout (node:internal/timers:605:17)
at process.processTimers (node:internal/timers:541:7) {
generatedMessage: false,
code: 'ERR_ASSERTION',
actual: false,
expected: true,
operator: '==',
diff: 'simple'
}
What do you see instead?
root@KContainer:~/51381# bun test b.test.cjs
bun test v1.3.11-canary.1 (9e93bfa1)
b.test.cjs:
✓ describe wrapper > callback test [1.25ms]
1 pass
0 fail
Ran 1 test across 1 file. [55.00ms]
Additional information
No response
Activity
robobun commentedon Mar 24, 2026
✅ Fix submitted: PR #28502
Root cause:
createTest()innode:testnever passed adonecallback to callback-style test functions — the test completed synchronously before async callbacks fired.Fix: Check
fn.length >= 2and pass a guarded done callback instead of completing immediately. Handles sync throws, async rejections, and double-call protection.CI status: Latest build failures are Zig compiler download infrastructure issues (not code-related). Awaiting retrigger.
Verification (local):
USE_SYSTEM_BUN=1→ 2 fail (bug exists)bun bd test→ 5 pass (fix works)fix: pass done callback to node:test callback-style tests
fix: pass done callback to node:test callback-style tests
computer4000 commentedon Mar 25, 2026
Verified. Bun's test runner passes assertions in async callbacks that should fail.
Why this matters: Tests with
donecallbacks that fail insetTimeout/async code will pass silently, hiding real bugs.Workaround: Avoid done-style tests. Use async/await pattern:
fix: pass done callback to node:test callback-style tests
node:test: support the (t, done) callback signature in tests and hooks
robobun commentedon Jul 24, 2026
Fixed by #32631.
Verified on main at df84f8d:
node:testdone-style tests now wait for the callback, so assertion failures inside async callbacks (e.g.setTimeout) correctly fail the test.vs 1498d7b (before fix):