Refactor tests

package com.fsck.k9.mail.filter;

import java.io.IOException;

import java.io.ByteArrayOutputStream;

import okio.Buffer;

import okio.ByteString;

import org.junit.Before;

import org.junit.Test;

import static junit.framework.Assert.assertEquals;

public class SmtpDataStuffingTest {

    private Buffer buffer;

    private SmtpDataStuffing smtpDataStuffing;

    @Before

    public void setUp() throws Exception {

        buffer = new Buffer();

        smtpDataStuffing = new SmtpDataStuffing(buffer.outputStream());

    }

    @Test

    public void smtpDotStuffing_stuffingOnlyDotTest() throws IOException {

        String expectedMessageAfterStuffing = "Hello dot\r\n..";

        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();

        SmtpDataStuffing smtpDataStuffingStream = new SmtpDataStuffing(byteArrayOutputStream);

        byte[] data = ByteString.encodeUtf8("Hello dot\r\n.").toByteArray();

        smtpDataStuffingStream.write(data);

        smtpDataStuffingStream.close();

        byteArrayOutputStream.close();

        String actualMessageAfterStuffing = ByteString.of(byteArrayOutputStream.toByteArray()).utf8();

        assertEquals(expectedMessageAfterStuffing, actualMessageAfterStuffing);

    public void dotAtStartOfLine() throws IOException {

        smtpDataStuffing.write(bytesFor("Hello dot\r\n."));

        assertEquals("Hello dot\r\n..", buffer.readUtf8());

    }

    @Test

    public void smtpDotStuffing_noStuffingDotTest() throws IOException {

        String expectedMessageAfterStuffing = "...Hello .. dots.";

        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();

        SmtpDataStuffing smtpDataStuffingStream = new SmtpDataStuffing(byteArrayOutputStream);

        byte[] data = ByteString.encodeUtf8("...Hello .. dots.").toByteArray();

        smtpDataStuffingStream.write(data);

        smtpDataStuffingStream.close();

        byteArrayOutputStream.close();

        String actualMessageAfterStuffing = ByteString.of(byteArrayOutputStream.toByteArray()).utf8();

        assertEquals(expectedMessageAfterStuffing, actualMessageAfterStuffing);

    public void dotAtStartOfStream() throws IOException {

        smtpDataStuffing.write(bytesFor("...Hello .. dots."));

        //FIXME: The first line is a line, too. So This should be dot stuffed.

        // See https://tools.ietf.org/html/rfc5321#section-4.5.2

        assertEquals("...Hello .. dots.", buffer.readUtf8());

    }

    @Test

    public void smtpDotStuffing_stuffingAndNoStuffingDotTest() throws IOException {

        String expectedMessageAfterStuffing = "\r\n..Hello . dots.\r\n...\r\n..\r\n....";

        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();

        SmtpDataStuffing smtpDataStuffingStream = new SmtpDataStuffing(byteArrayOutputStream);

        byte[] data = ByteString.encodeUtf8("\r\n.Hello . dots.\r\n..\r\n.\r\n...").toByteArray();

        smtpDataStuffingStream.write(data);

        smtpDataStuffingStream.close();

        byteArrayOutputStream.close();

        String actualMessageAfterStuffing = ByteString.of(byteArrayOutputStream.toByteArray()).utf8();

        assertEquals(expectedMessageAfterStuffing, actualMessageAfterStuffing);

    public void dotsThatNeedStuffingMixedWithOnesThatDoNot() throws IOException {

        smtpDataStuffing.write(bytesFor("\r\n.Hello . dots.\r\n..\r\n.\r\n..."));

        assertEquals("\r\n..Hello . dots.\r\n...\r\n..\r\n....", buffer.readUtf8());

    }

    private byte[] bytesFor(String input) {

        return ByteString.encodeUtf8(input).toByteArray();

    }

}