public function test_to_json()
{
$lines = array(new Line('foo', 11, 'bar'), new Line('baz', 2, 'something'));
$backtrace = new Backtrace($lines);
$expected = json_encode(array(array('file' => 'foo', 'number' => 11, 'method' => 'bar'), array('file' => 'baz', 'number' => 2, 'method' => 'something')));
$this->assertEquals($expected, $backtrace->to_json());
}