Laravel_PHPUnit_Tables_Truncate.md

File: tests/TestCase.php

use Illuminate\Support\Facades\DB;

public function tearDown()
{

    $sql = "SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES WHERE table_schema = 'YOUR_DATABASE_NAME';";

    DB::statement("SET FOREIGN_KEY_CHECKS = 0;");
    $tables = DB::select($sql);

    array_walk($tables, function($table){
        if ($table->TABLE_NAME != 'migrations') {
            DB::table($table->TABLE_NAME)->truncate();
        }
    });

    DB::statement("SET FOREIGN_KEY_CHECKS = 1;");
    parent::tearDown();
}

Why don't you try/catch to truncate function, so If there's an exception, you can catch it