/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You under the Apache License, Version 2.0
    * (the "License"); you may not use this file except in compliance with
    * the License.  You may obtain a copy of the License at
    *
    *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.commons.io.input;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertNotNull;
  import static org.junit.jupiter.api.Assertions.assertNull;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  import static org.junit.jupiter.api.Assertions.fail;
  
  import java.io.BufferedOutputStream;
  import java.io.BufferedReader;
  import java.io.File;
  import java.io.FileNotFoundException;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.OutputStreamWriter;
  import java.io.RandomAccessFile;
  import java.io.Writer;
  import java.nio.charset.Charset;
  import java.nio.charset.StandardCharsets;
  import java.nio.file.Files;
  import java.nio.file.StandardOpenOption;
  import java.nio.file.attribute.FileTime;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.List;
  import java.util.concurrent.CountDownLatch;
  import java.util.concurrent.Executor;
  import java.util.concurrent.Executors;
  import java.util.concurrent.ScheduledThreadPoolExecutor;
  import java.util.concurrent.TimeUnit;
  
  import org.apache.commons.io.FileUtils;
  import org.apache.commons.io.IOUtils;
  import org.apache.commons.io.RandomAccessFileMode;
  import org.apache.commons.io.TestResources;
  import org.apache.commons.io.test.TestUtils;
  import org.junit.jupiter.api.Test;
  import org.junit.jupiter.api.io.TempDir;
  
  /**
   * Test for {@link Tailer}.
   */
  public class TailerTest {
  
      private static final class NonStandardTailable implements Tailer.Tailable {
  
          private final File file;
  
          public NonStandardTailable(final File file) {
              this.file = file;
          }
  
          @Override
          public Tailer.RandomAccessResourceBridge getRandomAccess(final String mode) throws FileNotFoundException {
              return new Tailer.RandomAccessResourceBridge() {
  
                  private final RandomAccessFile randomAccessFile = new RandomAccessFile(file, mode);
  
                  @Override
                  public void close() throws IOException {
                      randomAccessFile.close();
                  }
  
                  @Override
                  public long getPointer() throws IOException {
                      return randomAccessFile.getFilePointer();
                  }
  
                  @Override
                  public int read(final byte[] b) throws IOException {
                      return randomAccessFile.read(b);
                  }
  
                  @Override
                  public void seek(final long position) throws IOException {
                      randomAccessFile.seek(position);
                  }
              };
          }
  
          @Override
         public boolean isNewer(final FileTime fileTime) throws IOException {
             return FileUtils.isFileNewer(file, fileTime);
         }
 
         @Override
         public FileTime lastModifiedFileTime() throws IOException {
             return FileUtils.lastModifiedFileTime(file);
         }
 
         @Override
         public long size() {
             return file.length();
         }
     }
 
     /**
      * Test {@link TailerListener} implementation.
      */
     private static final class TestTailerListener extends TailerListenerAdapter {
 
         // Must be synchronized because it is written by one thread and read by another
         private final List<String> lines = Collections.synchronizedList(new ArrayList<>());
 
         private final CountDownLatch latch;
 
         volatile Exception exception;
 
         volatile int notFound;
 
         volatile int rotated;
 
         volatile int initialized;
 
         volatile int reachedEndOfFile;
 
         public TestTailerListener() {
             latch = new CountDownLatch(1);
         }
 
         public TestTailerListener(final int expectedLines) {
             latch = new CountDownLatch(expectedLines);
         }
 
         public boolean awaitExpectedLines(final long timeout, final TimeUnit timeUnit) throws InterruptedException {
             return latch.await(timeout, timeUnit);
         }
 
         public void clear() {
             lines.clear();
         }
 
         @Override
         public void endOfFileReached() {
             reachedEndOfFile++; // not atomic, but OK because only updated here.
         }
 
         @Override
         public void fileNotFound() {
             notFound++; // not atomic, but OK because only updated here.
         }
 
         @Override
         public void fileRotated() {
             rotated++; // not atomic, but OK because only updated here.
         }
 
         public List<String> getLines() {
             return lines;
         }
 
         @Override
         public void handle(final Exception e) {
             exception = e;
         }
 
         @Override
         public void handle(final String line) {
             lines.add(line);
             latch.countDown();
         }
 
         @Override
         public void init(final Tailer tailer) {
             initialized++; // not atomic, but OK because only updated here.
         }
     }
 
     private static final int TEST_BUFFER_SIZE = 1024;
 
     private static final int TEST_DELAY_MILLIS = 1500;
 
     @TempDir
     public static File temporaryFolder;
 
     protected void createFile(final File file, final long size) throws IOException {
         assertTrue(file.getParentFile().exists(), () -> "Cannot create file " + file + " as the parent directory does not exist");
         try (BufferedOutputStream output = new BufferedOutputStream(Files.newOutputStream(file.toPath()))) {
             TestUtils.generateTestData(output, size);
         }
 
         // try to make sure file is found
         // (to stop continuum occasionally failing)
         RandomAccessFile reader = null;
         try {
             while (reader == null) {
                 try {
                     reader = RandomAccessFileMode.READ_ONLY.create(file);
                 } catch (final FileNotFoundException ignore) {
                     // ignore
                 }
                 TestUtils.sleepQuietly(200L);
             }
         } finally {
             IOUtils.closeQuietly(reader);
         }
         // sanity checks
         assertTrue(file.exists());
         assertEquals(size, file.length());
     }
 
     @Test
     @SuppressWarnings("squid:S2699") // Suppress "Add at least one assertion to this test case"
     public void testBufferBreak() throws Exception {
         final long delay = 50;
 
         final File file = new File(temporaryFolder, "testBufferBreak.txt");
         createFile(file, 0);
         writeString(file, "SBTOURIST\n");
 
         final TestTailerListener listener = new TestTailerListener();
         try (Tailer tailer = new Tailer(file, listener, delay, false, 1)) {
             final Thread thread = new Thread(tailer);
             thread.start();
 
             List<String> lines = listener.getLines();
             while (lines.isEmpty() || !lines.get(lines.size() - 1).equals("SBTOURIST")) {
                 lines = listener.getLines();
             }
 
             listener.clear();
         }
     }
 
     @Test
     public void testBuilderWithNonStandardTailable() throws Exception {
         final File file = new File(temporaryFolder, "tailer-create-with-delay-and-from-start-with-reopen-and-buffersize-and-charset.txt");
         createFile(file, 0);
         final TestTailerListener listener = new TestTailerListener(1);
         try (Tailer tailer = Tailer.builder()
                 .setExecutorService(Executors.newSingleThreadExecutor())
                 .setTailable(new NonStandardTailable(file))
                 .setTailerListener(listener)
                 .get()) {
             assertTrue(tailer.getTailable() instanceof NonStandardTailable);
             validateTailer(listener, file);
         }
     }
 
     @Test
     public void testCreate() throws Exception {
         final File file = new File(temporaryFolder, "tailer-create.txt");
         createFile(file, 0);
         final TestTailerListener listener = new TestTailerListener(1);
         try (Tailer tailer = Tailer.create(file, listener)) {
             validateTailer(listener, file);
         }
     }
 
     @Test
     public void testCreateWithDelay() throws Exception {
         final File file = new File(temporaryFolder, "tailer-create-with-delay.txt");
         createFile(file, 0);
         final TestTailerListener listener = new TestTailerListener(1);
         try (Tailer tailer = Tailer.create(file, listener, TEST_DELAY_MILLIS)) {
             validateTailer(listener, file);
         }
     }
 
     @Test
     public void testCreateWithDelayAndFromStart() throws Exception {
         final File file = new File(temporaryFolder, "tailer-create-with-delay-and-from-start.txt");
         createFile(file, 0);
         final TestTailerListener listener = new TestTailerListener(1);
         try (Tailer tailer = Tailer.create(file, listener, TEST_DELAY_MILLIS, false)) {
             validateTailer(listener, file);
         }
     }
 
     @Test
     public void testCreateWithDelayAndFromStartWithBufferSize() throws Exception {
         final File file = new File(temporaryFolder, "tailer-create-with-delay-and-from-start-with-buffersize.txt");
         createFile(file, 0);
         final TestTailerListener listener = new TestTailerListener(1);
         try (Tailer tailer = Tailer.create(file, listener, TEST_DELAY_MILLIS, false, TEST_BUFFER_SIZE)) {
             validateTailer(listener, file);
         }
     }
 
     @Test
     public void testCreateWithDelayAndFromStartWithReopenAndBufferSize() throws Exception {
         final File file = new File(temporaryFolder, "tailer-create-with-delay-and-from-start-with-reopen-and-buffersize.txt");
         createFile(file, 0);
         final TestTailerListener listener = new TestTailerListener(1);
         try (Tailer tailer = Tailer.create(file, listener, TEST_DELAY_MILLIS, false, true, TEST_BUFFER_SIZE)) {
             validateTailer(listener, file);
         }
     }
 
     @Test
     public void testCreateWithDelayAndFromStartWithReopenAndBufferSizeAndCharset() throws Exception {
         final File file = new File(temporaryFolder, "tailer-create-with-delay-and-from-start-with-reopen-and-buffersize-and-charset.txt");
         createFile(file, 0);
         final TestTailerListener listener = new TestTailerListener(1);
         try (Tailer tailer = Tailer.create(file, StandardCharsets.UTF_8, listener, TEST_DELAY_MILLIS, false, true, TEST_BUFFER_SIZE)) {
             validateTailer(listener, file);
         }
     }
 
     @Test
     public void testCreatorWithDelayAndFromStartWithReopen() throws Exception {
         final File file = new File(temporaryFolder, "tailer-create-with-delay-and-from-start-with-reopen.txt");
         createFile(file, 0);
         final TestTailerListener listener = new TestTailerListener(1);
         try (Tailer tailer = Tailer.create(file, listener, TEST_DELAY_MILLIS, false, false)) {
             validateTailer(listener, file);
         }
     }
 
     /*
      * Tests [IO-357][Tailer] InterruptedException while the thread is sleeping is silently ignored.
      */
     @Test
     public void testInterrupt() throws Exception {
         final File file = new File(temporaryFolder, "nosuchfile");
         assertFalse(file.exists(), "nosuchfile should not exist");
         final TestTailerListener listener = new TestTailerListener();
         // Use a long delay to try to make sure the test thread calls interrupt() while the tailer thread is sleeping.
         final int delay = 1000;
         final int idle = 50; // allow time for thread to work
         try (Tailer tailer = new Tailer(file, listener, delay, false, IOUtils.DEFAULT_BUFFER_SIZE)) {
             final Thread thread = new Thread(tailer);
             thread.setDaemon(true);
             thread.start();
             TestUtils.sleep(idle);
             thread.interrupt();
             TestUtils.sleep(delay + idle);
             assertNotNull(listener.exception, "Missing InterruptedException");
             assertTrue(listener.exception instanceof InterruptedException, "Unexpected Exception: " + listener.exception);
             assertEquals(1, listener.initialized, "Expected init to be called");
             assertTrue(listener.notFound > 0, "fileNotFound should be called");
             assertEquals(0, listener.rotated, "fileRotated should be not be called");
             assertEquals(0, listener.reachedEndOfFile, "end of file never reached");
         }
     }
 
     @Test
     public void testIO335() throws Exception { // test CR behavior
         // Create & start the Tailer
         final long delayMillis = 50;
         final File file = new File(temporaryFolder, "tailer-testio334.txt");
         createFile(file, 0);
         final TestTailerListener listener = new TestTailerListener();
         try (Tailer tailer = new Tailer(file, listener, delayMillis, false)) {
             final Thread thread = new Thread(tailer);
             thread.start();
 
             // Write some lines to the file
             writeString(file, "CRLF\r\n", "LF\n", "CR\r", "CRCR\r\r", "trail");
             final long testDelayMillis = delayMillis * 10;
             TestUtils.sleep(testDelayMillis);
             final List<String> lines = listener.getLines();
             assertEquals(4, lines.size(), "line count");
             assertEquals("CRLF", lines.get(0), "line 1");
             assertEquals("LF", lines.get(1), "line 2");
             assertEquals("CR", lines.get(2), "line 3");
             assertEquals("CRCR\r", lines.get(3), "line 4");
         }
     }
 
     @Test
     @SuppressWarnings("squid:S2699") // Suppress "Add at least one assertion to this test case"
     public void testLongFile() throws Exception {
         final long delay = 50;
 
         final File file = new File(temporaryFolder, "testLongFile.txt");
         createFile(file, 0);
         try (Writer writer = Files.newBufferedWriter(file.toPath(), StandardOpenOption.APPEND)) {
             for (int i = 0; i < 100000; i++) {
                 writer.write("LineLineLineLineLineLineLineLineLineLine\n");
             }
             writer.write("SBTOURIST\n");
         }
 
         final TestTailerListener listener = new TestTailerListener();
         try (Tailer tailer = new Tailer(file, listener, delay, false)) {
 
             // final long start = System.currentTimeMillis();
 
             final Thread thread = new Thread(tailer);
             thread.start();
 
             List<String> lines = listener.getLines();
             while (lines.isEmpty() || !lines.get(lines.size() - 1).equals("SBTOURIST")) {
                 lines = listener.getLines();
             }
             // System.out.println("Elapsed: " + (System.currentTimeMillis() - start));
 
             listener.clear();
         }
     }
 
     @Test
     public void testMultiByteBreak() throws Exception {
         // System.out.println("testMultiByteBreak() Default charset: " + Charset.defaultCharset().displayName());
         final long delay = 50;
         final File origin = TestResources.getFile("test-file-utf8.bin");
         final File file = new File(temporaryFolder, "testMultiByteBreak.txt");
         createFile(file, 0);
         final TestTailerListener listener = new TestTailerListener();
         final String osname = System.getProperty("os.name");
         final boolean isWindows = osname.startsWith("Windows");
         // Need to use UTF-8 to read & write the file otherwise it can be corrupted (depending on the default charset)
         final Charset charsetUTF8 = StandardCharsets.UTF_8;
         try (Tailer tailer = new Tailer(file, charsetUTF8, listener, delay, false, isWindows, IOUtils.DEFAULT_BUFFER_SIZE)) {
             final Thread thread = new Thread(tailer);
             thread.start();
 
             try (Writer out = new OutputStreamWriter(Files.newOutputStream(file.toPath()), charsetUTF8);
                 BufferedReader reader = new BufferedReader(new InputStreamReader(Files.newInputStream(origin.toPath()), charsetUTF8))) {
                 final List<String> lines = new ArrayList<>();
                 String line;
                 while ((line = reader.readLine()) != null) {
                     out.write(line);
                     out.write("\n");
                     lines.add(line);
                 }
                 out.close(); // ensure data is written
 
                 final long testDelayMillis = delay * 10;
                 TestUtils.sleep(testDelayMillis);
                 final List<String> tailerlines = listener.getLines();
                 assertEquals(lines.size(), tailerlines.size(), "line count");
                 for (int i = 0, len = lines.size(); i < len; i++) {
                     final String expected = lines.get(i);
                     final String actual = tailerlines.get(i);
                     if (!expected.equals(actual)) {
                         fail("Line: " + i + "\nExp: (" + expected.length() + ") " + expected + "\nAct: (" + actual.length() + ") " + actual);
                     }
                 }
             }
         }
     }
 
     @Test
     public void testSimpleConstructor() throws Exception {
         final File file = new File(temporaryFolder, "tailer-simple-constructor.txt");
         createFile(file, 0);
         final TestTailerListener listener = new TestTailerListener(1);
         try (Tailer tailer = new Tailer(file, listener)) {
             final Thread thread = new Thread(tailer);
             thread.start();
             validateTailer(listener, file);
         }
     }
 
     @Test
     public void testSimpleConstructorWithDelay() throws Exception {
         final File file = new File(temporaryFolder, "tailer-simple-constructor-with-delay.txt");
         createFile(file, 0);
         final TestTailerListener listener = new TestTailerListener(1);
         try (Tailer tailer = new Tailer(file, listener, TEST_DELAY_MILLIS)) {
             final Thread thread = new Thread(tailer);
             thread.start();
             validateTailer(listener, file);
         }
     }
 
     @Test
     public void testSimpleConstructorWithDelayAndFromStart() throws Exception {
         final File file = new File(temporaryFolder, "tailer-simple-constructor-with-delay-and-from-start.txt");
         createFile(file, 0);
         final TestTailerListener listener = new TestTailerListener(1);
         try (Tailer tailer = new Tailer(file, listener, TEST_DELAY_MILLIS, false)) {
             final Thread thread = new Thread(tailer);
             thread.start();
             validateTailer(listener, file);
         }
     }
 
     @Test
     public void testSimpleConstructorWithDelayAndFromStartWithBufferSize() throws Exception {
         final File file = new File(temporaryFolder, "tailer-simple-constructor-with-delay-and-from-start-with-buffersize.txt");
         createFile(file, 0);
         final TestTailerListener listener = new TestTailerListener(1);
         try (Tailer tailer = new Tailer(file, listener, TEST_DELAY_MILLIS, false, TEST_BUFFER_SIZE)) {
             final Thread thread = new Thread(tailer);
             thread.start();
             validateTailer(listener, file);
         }
     }
 
     @Test
     public void testSimpleConstructorWithDelayAndFromStartWithReopen() throws Exception {
         final File file = new File(temporaryFolder, "tailer-simple-constructor-with-delay-and-from-start-with-reopen.txt");
         createFile(file, 0);
         final TestTailerListener listener = new TestTailerListener(1);
         try (Tailer tailer = new Tailer(file, listener, TEST_DELAY_MILLIS, false, false)) {
             final Thread thread = new Thread(tailer);
             thread.start();
             validateTailer(listener, file);
         }
     }
 
     @Test
     public void testSimpleConstructorWithDelayAndFromStartWithReopenAndBufferSize() throws Exception {
         final File file = new File(temporaryFolder, "tailer-simple-constructor-with-delay-and-from-start-with-reopen-and-buffersize.txt");
         createFile(file, 0);
         final TestTailerListener listener = new TestTailerListener(1);
         try (Tailer tailer = new Tailer(file, listener, TEST_DELAY_MILLIS, false, true, TEST_BUFFER_SIZE)) {
             final Thread thread = new Thread(tailer);
             thread.start();
             validateTailer(listener, file);
         }
     }
 
     @Test
     public void testSimpleConstructorWithDelayAndFromStartWithReopenAndBufferSizeAndCharset() throws Exception {
         final File file = new File(temporaryFolder, "tailer-simple-constructor-with-delay-and-from-start-with-reopen-and-buffersize-and-charset.txt");
         createFile(file, 0);
         final TestTailerListener listener = new TestTailerListener(1);
         try (Tailer tailer = new Tailer(file, StandardCharsets.UTF_8, listener, TEST_DELAY_MILLIS, false, true, TEST_BUFFER_SIZE)) {
             final Thread thread = new Thread(tailer);
             thread.start();
             validateTailer(listener, file);
         }
     }
 
     @Test
     public void testStopWithNoFile() throws Exception {
         final File file = new File(temporaryFolder, "nosuchfile");
         assertFalse(file.exists(), "nosuchfile should not exist");
         final TestTailerListener listener = new TestTailerListener();
         final int delay = 100;
         final int idle = 50; // allow time for thread to work
         try (Tailer tailer = Tailer.create(file, listener, delay, false)) {
             TestUtils.sleep(idle);
         }
         TestUtils.sleep(delay + idle);
         if (listener.exception != null) {
             listener.exception.printStackTrace();
         }
         assertNull(listener.exception, "Should not generate Exception");
         assertEquals(1, listener.initialized, "Expected init to be called");
         assertTrue(listener.notFound > 0, "fileNotFound should be called");
         assertEquals(0, listener.rotated, "fileRotated should be not be called");
         assertEquals(0, listener.reachedEndOfFile, "end of file never reached");
     }
 
     @Test
     public void testStopWithNoFileUsingExecutor() throws Exception {
         final File file = new File(temporaryFolder, "nosuchfile");
         assertFalse(file.exists(), "nosuchfile should not exist");
         final TestTailerListener listener = new TestTailerListener();
         final int delay = 100;
         final int idle = 50; // allow time for thread to work
         try (Tailer tailer = new Tailer(file, listener, delay, false)) {
             final Executor exec = new ScheduledThreadPoolExecutor(1);
             exec.execute(tailer);
             TestUtils.sleep(idle);
         }
         TestUtils.sleep(delay + idle);
         assertNull(listener.exception, "Should not generate Exception");
         assertEquals(1, listener.initialized, "Expected init to be called");
         assertTrue(listener.notFound > 0, "fileNotFound should be called");
         assertEquals(0, listener.rotated, "fileRotated should be not be called");
         assertEquals(0, listener.reachedEndOfFile, "end of file never reached");
     }
 
     @Test
     public void testTailer() throws Exception {
 
         // Create & start the Tailer
         final long delayMillis = 50;
         final File file = new File(temporaryFolder, "tailer1-test.txt");
         createFile(file, 0);
         final TestTailerListener listener = new TestTailerListener();
         final String osname = System.getProperty("os.name");
         final boolean isWindows = osname.startsWith("Windows");
         try (Tailer tailer = new Tailer(file, listener, delayMillis, false, isWindows)) {
             final Thread thread = new Thread(tailer);
             thread.start();
 
             // Write some lines to the file
             write(file, "Line one", "Line two");
             final long testDelayMillis = delayMillis * 10;
             TestUtils.sleep(testDelayMillis);
             List<String> lines = listener.getLines();
             assertEquals(2, lines.size(), "1 line count");
             assertEquals("Line one", lines.get(0), "1 line 1");
             assertEquals("Line two", lines.get(1), "1 line 2");
             listener.clear();
 
             // Write another line to the file
             write(file, "Line three");
             TestUtils.sleep(testDelayMillis);
             lines = listener.getLines();
             assertEquals(1, lines.size(), "2 line count");
             assertEquals("Line three", lines.get(0), "2 line 3");
             listener.clear();
 
             // Check file does actually have all the lines
             lines = FileUtils.readLines(file, StandardCharsets.UTF_8);
             assertEquals(3, lines.size(), "3 line count");
             assertEquals("Line one", lines.get(0), "3 line 1");
             assertEquals("Line two", lines.get(1), "3 line 2");
             assertEquals("Line three", lines.get(2), "3 line 3");
 
             // Delete & re-create
             file.delete();
             assertFalse(file.exists(), "File should not exist");
             createFile(file, 0);
             assertTrue(file.exists(), "File should now exist");
             TestUtils.sleep(testDelayMillis);
 
             // Write another line
             write(file, "Line four");
             TestUtils.sleep(testDelayMillis);
             lines = listener.getLines();
             assertEquals(1, lines.size(), "4 line count");
             assertEquals("Line four", lines.get(0), "4 line 3");
             listener.clear();
 
             // Stop
             thread.interrupt();
             TestUtils.sleep(testDelayMillis * 4);
             write(file, "Line five");
             assertEquals(0, listener.getLines().size(), "4 line count");
             assertNotNull(listener.exception, "Missing InterruptedException");
             assertTrue(listener.exception instanceof InterruptedException, "Unexpected Exception: " + listener.exception);
             assertEquals(1, listener.initialized, "Expected init to be called");
             // assertEquals(0 , listener.notFound, "fileNotFound should not be called"); // there is a window when it might be
             // called
             assertEquals(1, listener.rotated, "fileRotated should be called");
         }
     }
 
     @Test
     public void testTailerEndOfFileReached() throws Exception {
         // Create & start the Tailer
         final long delayMillis = 50;
         final long testDelayMillis = delayMillis * 10;
         final File file = new File(temporaryFolder, "tailer-eof-test.txt");
         createFile(file, 0);
         final TestTailerListener listener = new TestTailerListener();
         final String osname = System.getProperty("os.name");
         final boolean isWindows = osname.startsWith("Windows");
         try (Tailer tailer = new Tailer(file, listener, delayMillis, false, isWindows)) {
             final Thread thread = new Thread(tailer);
             thread.start();
 
             // write a few lines
             write(file, "line1", "line2", "line3");
             TestUtils.sleep(testDelayMillis);
 
             // write a few lines
             write(file, "line4", "line5", "line6");
             TestUtils.sleep(testDelayMillis);
 
             // write a few lines
             write(file, "line7", "line8", "line9");
             TestUtils.sleep(testDelayMillis);
 
             // May be > 3 times due to underlying OS behavior wrt streams
             assertTrue(listener.reachedEndOfFile >= 3, "end of file reached at least 3 times");
         }
     }
 
     @Test
     public void testTailerEof() throws Exception {
         // Create & start the Tailer
         final long delayMillis = 100;
         final File file = new File(temporaryFolder, "tailer2-test.txt");
         createFile(file, 0);
         final TestTailerListener listener = new TestTailerListener();
         try (Tailer tailer = new Tailer(file, listener, delayMillis, false)) {
             final Thread thread = new Thread(tailer);
             thread.start();
 
             // Write some lines to the file
             writeString(file, "Line");
 
             TestUtils.sleep(delayMillis * 2);
             List<String> lines = listener.getLines();
             assertEquals(0, lines.size(), "1 line count");
 
             writeString(file, " one\n");
             TestUtils.sleep(delayMillis * 4);
             lines = listener.getLines();
 
             assertEquals(1, lines.size(), "1 line count");
             assertEquals("Line one", lines.get(0), "1 line 1");
 
             listener.clear();
         }
     }
 
     private void validateTailer(final TestTailerListener listener, final File file) throws IOException, InterruptedException {
         write(file, "foo");
         final int timeout = 30;
         final TimeUnit timeoutUnit = TimeUnit.SECONDS;
         assertTrue(listener.awaitExpectedLines(timeout, timeoutUnit), () -> String.format("await timed out after %s %s", timeout, timeoutUnit));
         assertEquals(listener.getLines(), Arrays.asList("foo"), "lines");
     }
 
     /** Appends lines to a file */
     private void write(final File file, final String... lines) throws IOException {
         try (Writer writer = Files.newBufferedWriter(file.toPath(), StandardOpenOption.APPEND)) {
             for (final String line : lines) {
                 writer.write(line + "\n");
             }
         }
     }
 
     /** Appends strings to a file */
     private void writeString(final File file, final String... strings) throws IOException {
         try (Writer writer = Files.newBufferedWriter(file.toPath(), StandardOpenOption.APPEND)) {
             for (final String string : strings) {
                 writer.write(string);
             }
         }
     }
 }