[lang-ref] Get source file path ( php )

<?php
public function testGetSourceFilePath(): void
{
	// __FILE__

	/* examples/get_source_file_path.php
		<?php
			function printFilePath(): void
			{
				echo(__FILE__);
			}
			if (realpath($argv[0]) === __FILE__) {
				printFilePath();
			}
	*/

	/* examples/get_source_file_path_call.php
		<?php
			require_once('get_source_file_path.php');
			printFilePath();
	*/

	$out = shell_exec('php examples/get_source_file_path.php');
	$this->assertStringEndsWith('/examples/get_source_file_path.php', $out);

	$out = shell_exec('php examples/get_source_file_path_call.php');
	$this->assertStringEndsWith('/examples/get_source_file_path.php', $out);
}