# Generate code coverage reports with the Bun test runner

Bun's test runner has built-in _code coverage reporting_. Use it to see how much of your codebase your tests cover, and where the gaps are.

---

Pass the `--coverage` flag to `bun test` to print a coverage report after the test run.

The report lists the source files the tests executed, the percentage of functions and lines that ran, and the line ranges that never ran.

```sh terminal icon="terminal"
bun test --coverage
```

```txt

test.test.ts:
✓ math > add [0.71ms]
✓ math > multiply [0.03ms]
✓ random [0.13ms]
-------------|---------|---------|-------------------
File         | % Funcs | % Lines | Uncovered Line #s
-------------|---------|---------|-------------------
All files    |   50.00 |   66.67 |
 math.ts     |   50.00 |   66.67 |
 random.ts   |   50.00 |   66.67 |
-------------|---------|---------|-------------------

 3 pass
 0 fail
 3 expect() calls
```

---

To enable coverage reporting by default, add the following to your `bunfig.toml`:

```toml bunfig.toml icon="settings"
[test]
coverage = true # always enable coverage
```

---

See [Code coverage](/test/code-coverage).