newly added a test testDecodeEncodedWords()

package com.fsck.k9.mail.internet;

import junit.framework.TestCase;

public class DecoderUtilTest extends TestCase {

    protected void setUp() throws Exception {

        super.setUp();

    }

    protected void tearDown() throws Exception {

        super.tearDown();

    }

    public void testDecodeEncodedWords() {

        String body, expect;

        MimeMessage message;

        body = "abc";

        expect = "abc";

        message = null;

        assertEquals(expect, DecoderUtil.decodeEncodedWords(body, message));

        body = "=?us-ascii?q?abc?=";

        expect = "abc";

        message = null;

        assertEquals(expect, DecoderUtil.decodeEncodedWords(body, message));

        body = "=?";

        expect = "=?";

        message = null;

        assertEquals(expect, DecoderUtil.decodeEncodedWords(body, message));

        body = "=??";

        expect = "=??";

        message = null;

        assertEquals(expect, DecoderUtil.decodeEncodedWords(body, message));

        body = "=???";

        expect = "=???";

        message = null;

        assertEquals(expect, DecoderUtil.decodeEncodedWords(body, message));

        body = "=????";

        expect = "=????";

        message = null;

        assertEquals(expect, DecoderUtil.decodeEncodedWords(body, message));

        body = "=????=";

        expect = "=????=";

        message = null;

        assertEquals(expect, DecoderUtil.decodeEncodedWords(body, message));

        body = "=??q??=";

        expect = "=??q??=";;

        message = null;

        assertEquals(expect, DecoderUtil.decodeEncodedWords(body, message));

        body = "=??q?a?=";

        expect = "=??q?a?=";

        //expect = "a";

        message = null;

        assertEquals(expect, DecoderUtil.decodeEncodedWords(body, message));

        body = "=??=";

        expect = "=??=";

        message = null;

        assertEquals(expect, DecoderUtil.decodeEncodedWords(body, message));

        body = "=?x?=";

        expect = "=?x?=";

        message = null;

        assertEquals(expect, DecoderUtil.decodeEncodedWords(body, message));

        body = "=?x??=";

        expect = "=?x??=";

        message = null;

        assertEquals(expect, DecoderUtil.decodeEncodedWords(body, message));

        body = "=?x?q?=";

        expect = "=?x?q?=";

        message = null;

        assertEquals(expect, DecoderUtil.decodeEncodedWords(body, message));

        body = "=?x?q??=";

        expect = "=?x?q??=";

        message = null;

        assertEquals(expect, DecoderUtil.decodeEncodedWords(body, message));

        body = "=?x?q?X?=";

        expect = "=?x?q?X?=";

        //expect = "X";

        message = null;

        assertEquals(expect, DecoderUtil.decodeEncodedWords(body, message));

        // invalid base64 string

        body = "=?us-ascii?b?abc?=";

        expect = "";

        message = null;

        assertEquals(expect, DecoderUtil.decodeEncodedWords(body, message));

        // broken encoded header

        body = "=?us-ascii?q?abc?= =?";

        expect = "abc =?";

        message = null;

        assertEquals(expect, DecoderUtil.decodeEncodedWords(body, message));

        body = "=?x?= =?";

        expect = "=?x?= =?";

        message = null;

        assertEquals(expect, DecoderUtil.decodeEncodedWords(body, message));

    }

}