Testing issue for pgsql_fallback

@effulgentsia: Thank for working on this. Some test failures you have come from the fact that the fallback driver is located in a module. In #3129043: Move core database drivers to modules of their own, I have the same problems. I fixed some test with the following code changes:

diff --git a/core/tests/Drupal/KernelTests/Core/Cache/EndOfTransactionQueriesTest.php b/core/tests/Drupal/KernelTests/Core/Cache/EndOfTransactionQueriesTest.php
index 7ff31796d4..1a0e4f6a7d 100644
--- a/core/tests/Drupal/KernelTests/Core/Cache/EndOfTransactionQueriesTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Cache/EndOfTransactionQueriesTest.php
@@ -31,12 +31,12 @@ class EndOfTransactionQueriesTest extends KernelTestBase {
    * {@inheritdoc}
    */
   protected function setUp(): void {
+    parent::setUp();
+
     if (!class_exists($this->getDatabaseConnectionInfo()['default']['namespace'] . '\Connection')) {
       $this->markTestSkipped(sprintf('No logging override exists for the %s database driver. Create it, subclass this test class and override ::getDatabaseConnectionInfo().', $this->getDatabaseConnectionInfo()['default']['driver']));
     }
 
-    parent::setUp();
-
     $this->installSchema('system', 'sequences');
     $this->installEntitySchema('entity_test');
     $this->installEntitySchema('user');
diff --git a/core/tests/Drupal/TestSite/Commands/TestSiteTearDownCommand.php b/core/tests/Drupal/TestSite/Commands/TestSiteTearDownCommand.php
index 0713af5c7c..6a37295998 100644
--- a/core/tests/Drupal/TestSite/Commands/TestSiteTearDownCommand.php
+++ b/core/tests/Drupal/TestSite/Commands/TestSiteTearDownCommand.php
@@ -80,6 +80,7 @@ protected function execute(InputInterface $input, OutputInterface $output) {
   protected function tearDown(TestDatabase $test_database, $db_url): void {
     // Connect to the test database.
     $root = dirname(dirname(dirname(dirname(dirname(__DIR__)))));
+    require_once $root . '/core/includes/bootstrap.inc';
     $database = Database::convertDbUrlToConnectionInfo($db_url, $root);
     $database['prefix'] = ['default' => $test_database->getDatabasePrefix()];
     Database::addConnectionInfo(__CLASS__, 'default', $database);
diff --git a/core/tests/Drupal/Tests/Core/Test/TestSetupTraitTest.php b/core/tests/Drupal/Tests/Core/Test/TestSetupTraitTest.php
index d0b8283566..d8d4d760bb 100644
--- a/core/tests/Drupal/Tests/Core/Test/TestSetupTraitTest.php
+++ b/core/tests/Drupal/Tests/Core/Test/TestSetupTraitTest.php
@@ -25,8 +25,10 @@ class TestSetupTraitTest extends UnitTestCase {
    * @covers ::changeDatabasePrefix
    */
   public function testChangeDatabasePrefix() {
+    $root = dirname(__FILE__, 7);
+    require_once $root . '/core/includes/bootstrap.inc';
     putenv('SIMPLETEST_DB=pgsql://user:pass@127.0.0.1/db');
-    $connection_info = Database::convertDbUrlToConnectionInfo('mysql://user:pass@localhost/db', '');
+    $connection_info = Database::convertDbUrlToConnectionInfo('mysql://user:pass@localhost/db', $root);
     Database::addConnectionInfo('default', 'default', $connection_info);
     $this->assertEquals('mysql', Database::getConnectionInfo()['default']['driver']);
     $this->assertEquals('localhost', Database::getConnectionInfo()['default']['host']);
@@ -35,7 +37,7 @@ public function testChangeDatabasePrefix() {
     // used to avoid unnecessary set up.
     $test_setup = $this->getMockForTrait(TestSetupTrait::class);
     $test_setup->databasePrefix = 'testDbPrefix';
-    $test_setup->root = '';
+    $test_setup->root = $root;
 
     $method = new \ReflectionMethod(get_class($test_setup), 'changeDatabasePrefix');
     $method->setAccessible(TRUE);
diff --git a/core/tests/Drupal/Tests/Scripts/TestSiteApplicationTest.php b/core/tests/Drupal/Tests/Scripts/TestSiteApplicationTest.php
index caabc84f75..c8e0a9e5f2 100644
--- a/core/tests/Drupal/Tests/Scripts/TestSiteApplicationTest.php
+++ b/core/tests/Drupal/Tests/Scripts/TestSiteApplicationTest.php
@@ -43,6 +43,7 @@ protected function setUp(): void {
     $php_executable_finder = new PhpExecutableFinder();
     $this->php = $php_executable_finder->find();
     $this->root = dirname(dirname(substr(__DIR__, 0, -strlen(__NAMESPACE__))));
+    require_once $this->root . '/core/includes/bootstrap.inc';
   }
 
   /**

I fixed the test Drupal\Tests\system\Functional\Module\InstallUninstallTest by making the module hidden.

@alexpott has problem with how the fallback driver is extending the classes of the by core supported PostgreSQL driver. I have no idea how to do it in another way. Waiting for another solution from @alexpott. When you have an idea how to solve it then please speak up.

I think one should not be able to uninstall the module that provides the database driver in use.

That would also imply that core's installer needs to enable the module if that's the selected driver.

That is next on my list. Right after #3129043: Move core database drivers to modules of their own has landed.

When I look at the changes in the current patch and I look at the patch from #3129043: Move core database drivers to modules of their own, I come to the conclusion that that issue is more or less blocking getting https://www.drupal.org/project/pgsql_fallback to pass the testbot.

If we want core to enforce that, then let's open an issue for that. That would also imply that core's installer needs to enable the module if that's the selected driver.

Created #3129534: Automatically enable the module that is providing the current database driver. This issue will block the improvement of the BackendCompilerPass. We need it to test the new BackendCompilerPass stuff.

Various Views tests, such as Drupal\Tests\datetime\Kernel\Views\FilterDateTimeTest, fail because they end up using the views.date_sql service (which is MySQL-specific) instead of the pgsql.views.date_sql service. The reason they don't use the latter is because per BackendCompilerPass, that's based on $container->get('database')->driver(), which for the fallback driver is PgsqlFallback, so we'd need a service named PgsqlFallback.views.date_sql.

I think we should improve BackendCompilerPass to check for a service based on $container->get('database')->databaseType() if it can't find one based on $container->get('database')->driver().

Created #3130973: Make the backend overridable service discovery also check the database type for an overridden service for fixing the problem.

Updated the patch with the patch from #3130973: Make the backend overridable service discovery also check the database type for an overridden service and a couple of other small improvements.

Rerolling the patch, because #3152003: EndOfTransactionQueriesTest does not include bootstrap.inc early enough for contrib database drivers and #3130973: Make the backend overridable service discovery also check the database type for an overridden service have landed.

Rerolling the patch, because #3151118: Include bootstrap.inc using composer has landed.