Added initial support for parallel testing

tests/TestCase.php

@@ -26,6 +26,7 @@ use Illuminate\Foundation\Testing\DatabaseTransactions;
 use Illuminate\Foundation\Testing\TestCase as BaseTestCase;
 use Illuminate\Http\JsonResponse;
 use Illuminate\Support\Env;
+use Illuminate\Support\Facades\DB;
 use Illuminate\Support\Facades\Log;
 use Illuminate\Testing\Assert as PHPUnit;
 use Monolog\Handler\TestHandler;
@@ -299,6 +300,8 @@ abstract class TestCase extends BaseTestCase
     /**
      * Run a set test with the given env variable.
      * Remembers the original and resets the value after test.
+     * Database config is juggled so the value can be restored when
+     * parallel testing are used, where multiple databases exist.
      */
     protected function runWithEnv(string $name, $value, callable $callback)
     {
@@ -311,7 +314,12 @@ abstract class TestCase extends BaseTestCase
             $_SERVER[$name] = $value;
         }
 
+        $database = config('database.connections.mysql_testing.database');
         $this->refreshApplication();
+
+        DB::purge();
+        config()->set('database.connections.mysql_testing.database', $database);
+
         $callback();
 
         if (is_null($originalVal)) {