Change SchemaUniquePrefixedKeysIndexTest to extend DriverSpecificDatabaseTestBase

I've created the patch so instead of relying on a extra function we now set the value depending on the driver class.

So the naming had to be TestBase instead of Test, so the testbot does not run it. This way it should work.

+++ b/core/modules/mysql/tests/src/Kernel/mysql/SchemaUniquePrefixedKeysIndexTest.php
@@ -0,0 +1,19 @@
+use Drupal\KernelTests\Core\Database\SchemaUniquePrefixedKeysIndexTestBase as CoreSchemaUniquePrefixedKeysIndexTest;

+++ b/core/modules/pgsql/tests/src/Kernel/pgsql/SchemaUniquePrefixedKeysIndexTest.php
@@ -0,0 +1,19 @@
+use Drupal\KernelTests\Core\Database\SchemaUniquePrefixedKeysIndexTestBase as CoreSchemaUniquePrefixedKeysIndexTest;

+++ b/core/modules/sqlite/tests/src/Kernel/sqlite/SchemaUniquePrefixedKeysIndexTest.php
@@ -0,0 +1,19 @@
+use Drupal\KernelTests\Core\Database\SchemaUniquePrefixedKeysIndexTestBase as CoreSchemaUniquePrefixedKeysIndexTest;

I don't think an alias is needed, here just extend SchemaUniquePrefixedKeysIndexTestBase ?

@mondrake that's true, changed the naming so we don't have the alias anymore.

+++ b/core/tests/Drupal/KernelTests/Core/Database/SchemaUniquePrefixedKeysIndexTestBase.php
@@ -7,16 +7,19 @@
+  protected $columnValue;

you can typehint the property directly in PHP 8.1, and skip the annotation

protected string $columnValue;

Added the change suggested by @mondrake.

I am afraid you need to do the same on the extending classes...

@mondrake That's true my bad. added the string typehint to the other classes.

1. +++ b/core/tests/Drupal/KernelTests/Core/Database/SchemaUniquePrefixedKeysIndexTestBase.php
   @@ -7,16 +7,17 @@
   +   * Set the value used to test the Schema unique prefixed keys index.
   

   Schema -> schema

2. +++ b/core/tests/Drupal/KernelTests/Core/Database/SchemaUniquePrefixedKeysIndexTestBase.php
   @@ -109,27 +104,11 @@ protected function checkUniqueConstraintException(string $table, string $column)
   -   * The basic syntax of passing an array (field, prefix length) as a key column
   -   * specifier must always be accepted by the driver. However, due to technical
   -   * limitations, some drivers may choose to ignore them.
   -   *
   -   * @return bool
   -   *   TRUE if the current database (driver) will conform to the prefix length
   -   *   specified as part of a key column specifier, FALSE if it will be ignored.
   

   We are losing this comment, and without it it is not at all obvious why Postgres/SQLite are different to MySQL. I think it would be good to move some of this explanation to the property declaration in the base class?

I've adjusted the comments based on the feedback from @longwave.

I adjusted the "lost" comment to what I think is a better description of the current situation.

Committed and pushed 224543f183 to 11.x (10.2.x). Thanks!