parts.nextPart()
    }.also { expected ->
      assertThat(expected).hasMessage("expected at least 1 part")
    }
  }

  @Test fun `skip preamble`() {
    val multipart =
      """
      |this is the preamble! it is invisible to application code
      |
      |--simple boundary
      |
      |abcd
      |--simple boundary--
      """.trimMargin()
        .replace("\n", "\r\n")

 Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
 Everyone is permitted to copy and distribute verbatim copies
 of this license document, but changing it is not allowed.

                            Preamble

  The GNU Affero General Public License is a free, copyleft license for
software and other kinds of works, specifically designed to ensure
cooperation with the community in the case of network server software.

(This is the first released version of the Lesser GPL.  It also counts
 as the successor of the GNU Library Public License, version 2, hence
 the version number 2.1.)

                            Preamble

  The licenses for most software are designed to take away your
freedom to share and change it.  By contrast, the GNU General Public
Licenses are intended to guarantee your freedom to share and change

51 Franklin Street, Fifth Floor
Boston, MA 02110-1335
USA

Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.

Preamble

The licenses for most software are designed to take away your freedom to
share and change it. By contrast, the GNU General Public License is
intended to guarantee your freedom to share and change free software--to