Add unit test for attached inner messages

package com.fsck.k9.mailstore

import java.io.ByteArrayInputStream

import com.fsck.k9.mail.internet.MimeBodyPart

import com.fsck.k9.mail.internet.MimeMessage

import com.fsck.k9.mail.internet.MimeMultipart

import org.junit.Test

import org.junit.Assert.*

class MimePartStreamParserTest {

    @Test

    fun innerMessage_DispositionInline() {

        val msg = MimePartStreamParser.parse(null, ByteArrayInputStream(("""From: <x@example.org>

To: <y@example.org>

Subject: Testmail 1

Content-Type: multipart/mixed; boundary=1

--1

Content-Type: text/plain

some text in the first part

--1

Content-Type: message/rfc822; name="message"

To: <z@example.org>

Subject: Hi

Date: now

Content-Type: text/plain

inner text

--1--""").toByteArray()))

        val body = msg.body as MimeMultipart

        assertEquals(2, body.count.toLong())

        val messagePart = body.getBodyPart(1) as MimeBodyPart

        assertEquals("message/rfc822", messagePart.mimeType)

        assertTrue(messagePart.body is MimeMessage)

    }

    @Test

    fun innerMessage_dispositionAttachment() {

        val msg = MimePartStreamParser.parse(null, ByteArrayInputStream(("""From: <x@example.org>

To: <y@example.org>

Subject: Testmail 2

Content-Type: multipart/mixed; boundary=1

--1

Content-Type: text/plain

some text in the first part

--1

Content-Type: message/rfc822; name="message"

Content-Disposition: attachment

To: <z@example.org>

Subject: Hi

Date: now

Content-Type: text/plain

inner text

--1--""").toByteArray()))

        val body = msg.body as MimeMultipart

        assertEquals(2, body.count)

        val messagePart = body.getBodyPart(1) as MimeBodyPart

        assertEquals("message/rfc822", messagePart.mimeType)

        assertTrue(messagePart.body is DeferredFileBody)

    }

}

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