Add unit test for attached inner messages

k9mail/src/test/java/com/fsck/k9/mailstore/MimePartStreamParserTest.kt

@@ -0,0 +1,75 @@
+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)
+    }
+}