SchemaTest.php

<?php

namespace Drupal\Tests\pgsql\Kernel\pgsql;

use Drupal\KernelTests\Core\Database\DriverSpecificSchemaTestBase;

/**
 * Tests schema API for the PostgreSQL driver.
 *
 * @group Database
 */
class SchemaTest extends DriverSpecificSchemaTestBase {
    
    /**
     * @covers \Drupal\Core\Database\Driver\pgsql\Schema::extensionExists
     */
    public function testPgsqlExtensionExists() : void {
        // Test the method for a non existing extension.
        $this->assertFalse($this->schema
            ->extensionExists('non_existing_extension'));
        // Test the method for an existing extension.
        $this->assertTrue($this->schema
            ->extensionExists('pg_trgm'));
    }

}