# Generate code coverage reports with the Bun test runner (/docs/guides/test/coverage)

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Related: [Run your tests with the Bun test runner](/docs/guides/test/run-tests.md), [Run tests in watch mode with Bun](/docs/guides/test/watch-mode.md), [Migrate from Jest to Bun's test runner](/docs/guides/test/migrate-from-jest.md), [Mock functions in `bun test`](/docs/guides/test/mock-functions.md), [Spy on methods in `bun test`](/docs/guides/test/spy-on.md), [Set the system time in Bun's test runner](/docs/guides/test/mock-clock.md)

Bun's test runner has built-in *code coverage reporting*. Use it to see how much of your codebase is covered by tests, 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    |   66.67 |   77.78 |
 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).