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bun.sh/packages
robobun 1a23797e82 feat: add test.serial() API for forcing serial test execution (#22899)
## Summary

Adds a new `test.serial()` API that forces tests to run serially even
when the `--concurrent` flag is passed. This is the opposite of
`test.concurrent()` which forces parallel execution.

## Motivation

Some tests genuinely need to run serially even in CI environments with
`--concurrent`:
- Database migration tests that must run in order
- Tests that modify shared global state
- Tests that use fixed ports or file system resources
- Tests that depend on timing or resource constraints

## Implementation

Changed `self_concurrent` from `bool` to `?bool`:
- `null` = default behavior (inherit from parent or use default)
- `true` = force concurrent execution
- `false` = force serial execution

## API Surface

```javascript
// Force serial execution
test.serial("database migration", async () => {
  // This runs serially even with --concurrent flag
});

// All modifiers work
test.serial.skip("skip this serial test", () => {});
test.serial.todo("implement this serial test");
test.serial.only("only run this serial test", () => {});
test.serial.each([[1], [2]])("serial test %i", (n) => {});
test.serial.if(condition)("conditional serial", () => {});

// Works with describe too
describe.serial("serial test suite", () => {
  test("test 1", () => {}); // runs serially
  test("test 2", () => {}); // runs serially
});

// Explicit test-level settings override describe-level
describe.concurrent("concurrent suite", () => {
  test.serial("this runs serially", () => {}); // serial wins
  test("this runs concurrently", () => {});
});
```

## Test Coverage

Comprehensive tests added including:
- Basic `test.serial()` functionality
- All modifiers (skip, todo, only, each, if)
- `describe.serial()` blocks
- Mixing serial and concurrent tests in same describe block
- Nested describe blocks with conflicting settings
- Explicit overrides (test.serial in describe.concurrent and vice versa)

All 36 tests pass 

## Example

```javascript
// Without this PR - these tests might run in parallel with --concurrent
test("migrate database schema v1", async () => { await migrateV1(); });
test("migrate database schema v2", async () => { await migrateV2(); });
test("migrate database schema v3", async () => { await migrateV3(); });

// With this PR - guaranteed serial execution
test.serial("migrate database schema v1", async () => { await migrateV1(); });
test.serial("migrate database schema v2", async () => { await migrateV2(); });
test.serial("migrate database schema v3", async () => { await migrateV3(); });
```

🤖 Generated with [Claude Code](https://claude.ai/code)

---------

Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
2025-09-23 21:06:06 -07:00
..
2025-09-12 01:08:46 -07:00