Version
v24.9.0
Platform
Linux home 5.15.0-153-generic #163-Ubuntu SMP Thu Aug 7 16:37:18 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux
Subsystem
No response
What steps will reproduce the bug?
runner.js
import { run } from "node:test";
import { spec } from "node:test/reporters";
const stream = run({
isolation: "none",
coverage: true,
});
stream.compose(spec).pipe(process.stdout);dummy.test.js
import { describe, it } from "node:test";
import * as assert from "node:assert";
describe("suite", () => {
it("works", () => {
assert.ok(true);
});
});How often does it reproduce? Is there a required condition?
Always. No.
What is the expected behavior? Why is that the expected behavior?
With isolation: "process" (the default), here's the output:
▶ suite
✔ works (0.789789ms)
✔ suite (2.636181ms)
ℹ tests 1
ℹ suites 1
ℹ pass 1
ℹ fail 0
ℹ cancelled 0
ℹ skipped 0
ℹ todo 0
ℹ duration_ms 77.285385
ℹ start of coverage report
ℹ -----------------------------------------------------------------
ℹ file | line % | branch % | funcs % | uncovered lines
ℹ -----------------------------------------------------------------
ℹ test | | | |
ℹ dummy.test.js | 100.00 | 100.00 | 100.00 |
ℹ -----------------------------------------------------------------
ℹ all files | 100.00 | 100.00 | 100.00 |
ℹ -----------------------------------------------------------------
ℹ end of coverage report
What do you see instead?
With isolation: "none", here's the output:
▶ suite
✔ works (0.979666ms)
✔ suite (2.172736ms)
ℹ tests 1
ℹ suites 1
ℹ pass 1
ℹ fail 0
ℹ cancelled 0
ℹ skipped 0
ℹ todo 0
ℹ duration_ms 28.684242
ℹ start of coverage report
ℹ ----------------------------------------------------------
ℹ file | line % | branch % | funcs % | uncovered lines
ℹ ----------------------------------------------------------
ℹ ----------------------------------------------------------
ℹ all files | 100.00 | 100.00 | 100.00 |
ℹ ----------------------------------------------------------
ℹ end of coverage report
(empty coverage)
The test stream emits a "test:coverage" event, but it is empty:
[Object: null prototype] {
nesting: 0,
summary: [Object: null prototype] {
workingDirectory: '/home/damien/git/socket.io/tmp',
files: [],
totals: [Object: null prototype] {
totalLineCount: 0,
totalBranchCount: 0,
totalFunctionCount: 0,
coveredLineCount: 0,
coveredBranchCount: 0,
coveredFunctionCount: 0,
coveredLinePercent: 100,
coveredBranchPercent: 100,
coveredFunctionPercent: 100
},
thresholds: [Object: null prototype] { line: 0, branch: 0, function: 0 }
}
}Additional information
No response
Version
v24.9.0
Platform
Subsystem
No response
What steps will reproduce the bug?
runner.js
dummy.test.js
How often does it reproduce? Is there a required condition?
Always. No.
What is the expected behavior? Why is that the expected behavior?
With
isolation: "process"(the default), here's the output:What do you see instead?
With
isolation: "none", here's the output:(empty coverage)
The test stream emits a "test:coverage" event, but it is empty:
Additional information
No response