Pest Version 5.3.2 Contains Critical Bug In Parallel Test Sharding
A bug in Pest 5.3.2 causes the parallel test runner to silently skip PHPUnit-formatted tests when using time-balanced sharding in CI environments.
Pest version 5.3.2 contains a critical bug affecting test execution in continuous integration workflows.
When you use the parallelization features, the time-balanced sharding mechanism fails to include standard PHPUnit tests in the runner. The issue occurs during command execution with the --parallel flag and parameters like --processes=2 --shard=1/2. Under these conditions, the framework silently ignores tests written in the PHPUnit format. This creates incomplete test suites without triggering an error or failure notification. Build logs can show that all tests passed even though a large portion of the codebase was skipped.
If you rely on parallel testing for large PHP projects, you should verify your test coverage reports during CI runs. Because the bug results in skipped tests rather than a crash, it may not be immediately obvious that the test suite is failing to execute as expected.
Maintenance teams are investigating the issue in the project repository. Until a patch is released, you may need to disable sharding or revert to a previous version of the framework to ensure all test cases are correctly processed.