Upgrade to Laravel 9 (#4413)

Co-authored-by: DaneEveritt <dane@daneeveritt.com>

tests/Traits/MocksPdoConnection.php

@@ -7,21 +7,17 @@ use Mockery;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\MySqlConnection;
 use Illuminate\Database\ConnectionResolver;
+use Illuminate\Database\ConnectionResolverInterface;
 
 trait MocksPdoConnection
 {
-    /**
-     * @var \Illuminate\Database\ConnectionResolverInterface|null
-     */
-    private static $initialResolver;
+    private static ?ConnectionResolverInterface $initialResolver;
 
     /**
      * Generates a mock PDO connection and injects it into the models so that any actual
      * DB call can be properly intercepted.
-     *
-     * @return \Mockery\MockInterface
      */
-    protected function mockPdoConnection()
+    protected function mockPdoConnection(): Mockery\MockInterface
     {
         self::$initialResolver = Model::getConnectionResolver();
 
@@ -39,7 +35,7 @@ trait MocksPdoConnection
     /**
      * Resets the mock state.
      */
-    protected function tearDownPdoMock()
+    protected function tearDownPdoMock(): void
     {
         if (!self::$initialResolver) {
             return;