Disconnecting the database connection after testing (#49327)

* Disconnection after testing with traits for database testing

* Revert "Disconnection after testing with traits for database testing"

This reverts commit 71c6653.

* Disconnection at teardown

* No need to disconnect for individual traits

* fix: Behavior when run without database

* Avoid changing the behavior before fixing as much as possible.

* Update TestCase.php

---------

Co-authored-by: Taylor Otwell <taylor@laravel.com>

src/Illuminate/Foundation/Testing/DatabaseTransactions.php

@@ -33,7 +33,7 @@ public function beginDatabaseTransaction()
                 $connection->unsetEventDispatcher();
                 $connection->rollBack();
                 $connection->setEventDispatcher($dispatcher);
-                $connection->disconnect();
+                $database->purge($name);
             }
         });
     }

src/Illuminate/Foundation/Testing/RefreshDatabase.php

@@ -109,7 +109,7 @@ public function beginDatabaseTransaction()
                 $connection->unsetEventDispatcher();
                 $connection->rollBack();
                 $connection->setEventDispatcher($dispatcher);
-                $connection->disconnect();
+                $database->purge($name);
             }
         });
     }

src/Illuminate/Foundation/Testing/TestCase.php

@@ -197,6 +197,12 @@ protected function tearDown(): void
 
             ParallelTesting::callTearDownTestCaseCallbacks($this);
 
+            $database = $this->app['db'] ?? null;
+
+            foreach (array_keys($database?->getConnections() ?? []) as $name) {
+                $database->purge($name);
+            }
+
             $this->app->flush();
 
             $this->app = null;