Add simple test to check if writing a parsed message leads to input data

tests/src/com/fsck/k9/mail/ReconstructMessageTest.java

@@ -0,0 +1,67 @@
+package com.fsck.k9.mail;
+
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+import android.test.AndroidTestCase;
+
+import com.fsck.k9.mail.internet.BinaryTempFileBody;
+import com.fsck.k9.mail.internet.MimeMessage;
+
+
+public class ReconstructMessageTest extends AndroidTestCase {
+
+    public void testMessage() throws IOException, MessagingException {
+        String messageSource =
+                "From: from@example.com\r\n" +
+                "To: to@example.com\r\n" +
+                "Subject: Test Message \r\n" +
+                "Date: Thu, 13 Nov 2014 17:09:38 +0100\r\n" +
+                "MIME-Version: 1.0\r\n" +
+                "Content-Type: multipart/mixed;\r\n" +
+                " boundary=\"----Boundary\"\r\n" +
+                "Content-Transfer-Encoding: 8bit\r\n" +
+                "\r\n" +
+                "This is a multipart MIME message.\r\n" +
+                "------Boundary\r\n" +
+                "Content-Type: text/plain; charset=utf-8\r\n" +
+                "Content-Transfer-Encoding: 8bit\r\n" +
+                "\r\n" +
+                "Testing.\r\n" +
+                "This is a text body with some greek characters.\r\n" +
+                "αβγδεζηθ\r\n" +
+                "End of test.\r\n" +
+                "\r\n" +
+                "------Boundary\r\n" +
+                "Content-Type: text/plain\r\n" +
+                "Content-Transfer-Encoding: quoted-printable\r\n" +
+                "\r\n" +
+                "=2E=2E=2E\r\n" +
+                "\r\n" +
+                "------Boundary--\r\n";
+
+        BinaryTempFileBody.setTempDirectory(getContext().getCacheDir());
+
+        InputStream messageInputStream = new ByteArrayInputStream(messageSource.getBytes());
+        MimeMessage message;
+        try {
+            message = new MimeMessage(messageInputStream, true);
+        } finally {
+            messageInputStream.close();
+        }
+
+        ByteArrayOutputStream messageOutputStream = new ByteArrayOutputStream();
+        try {
+            message.writeTo(messageOutputStream);
+        } finally {
+            messageOutputStream.close();
+        }
+
+        String reconstructedMessage = new String(messageOutputStream.toByteArray());
+
+        assertEquals(messageSource, reconstructedMessage);
+    }
+}