This package provides stub declarations for the WordPress Test Library.
The stubs were generated directly from the source code with the help of php-stubs/generator.
composer require --dev wildwolf/wordpress-test-library-stubs
Update your Psalm configuration file to include the following code:
<stubs>
<file name="vendor/wildwolf/wordpress-test-library-stubs/wordpress-test-library-stubs.php" />
</stubs>