GuzzleHttp\Tests\Psr7\FunctionsTest::testCopiesToStream PHP Метод

    public function testCopiesToStream()
    {
        $s1 = Psr7\stream_for('foobaz');
        $s2 = Psr7\stream_for('');
        Psr7\copy_to_stream($s1, $s2);
        $this->assertEquals('foobaz', (string) $s2);
        $s2 = Psr7\stream_for('');
        $s1->seek(0);
        Psr7\copy_to_stream($s1, $s2, 3);
        $this->assertEquals('foo', (string) $s2);
        Psr7\copy_to_stream($s1, $s2, 3);
        $this->assertEquals('foobaz', (string) $s2);
    }