[Bug]: --shard silently drops test files with non-Tests\ namespaces (e.g. modular app structures)

[Orrison]

What Happened

The --shard option silently ignores test classes whose fully-qualified name does not start with Tests\. This affects any project with test files outside the standard tests/ directory — such as modular Laravel applications with test directories like app-modules/*/tests/.

Root Cause

In src/Plugins/Shard.php, the allTests() method parses --list-tests output with this regex:

preg_match_all('/ - (?:P\\\\)?(Tests\\\\[^:]+)::/', $output, $matches);

This hardcodes that the class identifier after the P\ prefix must start with Tests\. However, when tests live outside the tests/ directory, Pest generates path-based identifiers like:

 - P\Appmodules\ai\tests\Tenant\Actions\SomeTest::__pest_evaluable_...

After stripping P\, the remaining identifier starts with Appmodules\, not Tests\, so the regex never matches.

Impact

In my project:

• 2540 total test cases in the Tenant suite
• 189 matched by the regex (tests in tests/Tenant/)
• 2351 silently dropped (tests in app-modules/*/tests/Tenant/)

The shard reports "16 files ran, out of 16" because it only sees 16 test files total. The remaining ~90% of the test suite is invisible to sharding — they either all run unsharded in every shard (wasting CI time) or are filtered out entirely by the --filter argument.

There is no warning or error indicating that tests were missed.

Expected Behavior

The regex should match any test class identifier from --list-tests output, not just those namespaced under Tests\. A fix would be:

preg_match_all('/ - (?:P\\\\)?([^:]+)::/', $output, $matches);

How to Reproduce

1. Create a project with tests outside tests/ (e.g. in app-modules/module-name/tests/)
2. Configure phpunit.xml testsuite to include those directories
3. Run pest --testsuite=YourSuite --shard=1/2
4. Observe the shard only reports tests from tests/ — app-module tests are missing

Sample Repository

canyongbs/advisingapp#2549

Pest Version

v4.7.0

PHP Version

8.4

Operation System

macOS

Notes

• Pest v4.7.0
• PHP 8.4
• Laravel modular application with ~40 modules in app-modules/

[mozex]

Take a look at this: https://mozex.dev/blog/2-fixing-pest-sharding-for-modular-laravel-applications

[Orrison]

Take a look at this: https://mozex.dev/blog/2-fixing-pest-sharding-for-modular-laravel-applications

@mozex Ah, yes. I found the issue as well. Opened a PR to fix it that hopefully gets merged in: #1713.

WDYT of my submission compared to your override code-wise?

[mozex]

@Orrison Just looked at #1713. Yours is actually better than mine.

My regex still anchors on Tests\ being in the FQCN (case-sensitive), which fits the Modules\Blog\Tests\Feature\PostTest shape I had in mind but would silently drop your own sample (P\Appmodules\ai\tests\Tenant\Actions\SomeTest, lowercase tests). Yours just trusts the --list-tests format and grabs everything before ::, so it works regardless of namespace convention.

Hoping it lands soon so I can drop the override.

[cschanhniem]

The regex in src/Plugins/Shard.php is the smoking gun. The fix is straightforward — drop the hardcoded Tests\\\\ prefix requirement:

// Current (line ~40 in Shard.php):
preg_match_all('/ - (?:P\\\\\\\\)?(Tests\\\\\\\\[^:]+)::/', $output, $matches);

// Fix:
preg_match_all('/ - (?:P\\\\\\\\)?([^:]+)::/', $output, $matches);

The P\\ prefix stripping already handles the path-to-namespace translation. The only thing Tests\\\\ was doing was filtering — and it filters incorrectly. Test classes are just PHP classes like any other; Pest's --list-tests output format guarantees - P\\Namespace\\Class::method. There's no reason to namespace-gate after stripping the P\\.

Two additional things worth considering:

1. After the regex fix, the allTests() method should also warn or log a count mismatch (filesScanned vs patterns matched) so silent drops become visible.
2. The same hardcoding may exist in the --filter generation path for shard splitting.

This is a one-line regex fix. The downstream impact is non-trivial: any project using a modular/non-standard directory structure (DDD, hexagonal, src/-based tests) silently runs incomplete or duplicated test suites in CI. For teams using AI agents to generate tests in non-standard paths — increasingly common with Copilot/Cursor in monorepos — this bug means agent-authored tests get zero coverage from sharded CI, creating a false safety signal. Tools like AGENTOWNERS help enforce that agent-contributed test files land in scanned paths, but only if the scanner sees them.