@phpunit @ssemicolons oh, missed that! Thank you for the heads up!
Looks like a really useful addition! Thanks @sebastian !

For reference, here is the feature's documentation: https://docs.phpunit.de/en/13.0/test-doubles.html#sealed-test-doubles

#php #phpunit #testdoubles #phpunit13

6. Test Doubles — PHPUnit 13.0 Manual

I am very excited about the new seal() method in #phpunit13 for one main reason: I have encountered too many tests that "passed despite unexpected method calls because unconfigured methods simply returned null" @phpunit