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  package com.jcabi.log;
  
  import java.io.ByteArrayInputStream;
  import java.io.Closeable;
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.StringWriter;
  import java.util.Timer;
  import java.util.TimerTask;
  import java.util.concurrent.CountDownLatch;
  import java.util.concurrent.TimeUnit;
  import java.util.logging.Level;
  import org.apache.commons.lang3.StringUtils;
  import org.apache.commons.lang3.SystemUtils;
  import org.apache.log4j.SimpleLayout;
  import org.apache.log4j.WriterAppender;
  import org.apache.log4j.spi.Filter;
  import org.apache.log4j.spi.LoggingEvent;
  import org.hamcrest.MatcherAssert;
  import org.hamcrest.Matchers;
  import org.junit.jupiter.api.Assertions;
  import org.junit.jupiter.api.Assumptions;
  import org.junit.jupiter.api.Disabled;
  import org.junit.jupiter.api.Test;
  import org.mockito.Mockito;
  
  /**
   * Test case for {@link VerboseProcess}.
   *
   * @checkstyle MultipleStringLiterals (500 lines)
   * @checkstyle ClassDataAbstractionCoupling (200 lines)
   * @todo #18 Locale/encoding problem in two test methods here. I'm not
   *  sure how to fix them, but they should be fixed. They fail on some
   *  machines, while run perfectly on others. They also fail when being
   *  executed from IntelliJ.
   * @since 0.1
   */
  @SuppressWarnings({ "PMD.TooManyMethods", "PMD.AvoidDuplicateLiterals" })
  final class VerboseProcessTest {
  
      @Test
      @Disabled
      void runsACommandLineScript() {
          Assumptions.assumeFalse(SystemUtils.IS_OS_WINDOWS, "");
          final VerboseProcess process = new VerboseProcess(
              new ProcessBuilder("echo", "hey \u20ac!").redirectErrorStream(true)
          );
          MatcherAssert.assertThat(
              process.stdout(),
              Matchers.containsString("\u20ac!")
          );
      }
  
      @Test
      @Disabled
      void echosUnicodeCorrectly() {
          Assumptions.assumeFalse(SystemUtils.IS_OS_WINDOWS, "");
          MatcherAssert.assertThat(
              new VerboseProcess(
                  new ProcessBuilder(
                      "/bin/bash", "-c",
                      "echo -n \u0442\u0435\u0441\u0442 | hexdump"
                  )
              ).stdout(),
              Matchers.containsString("0000000 d1 82 d0 b5 d1 81 d1 82")
          );
      }
  
     @Test
     void runsACommandLineScriptWithException() {
         Assumptions.assumeFalse(SystemUtils.IS_OS_WINDOWS, "");
         final VerboseProcess process = new VerboseProcess(
             new ProcessBuilder("cat", "/non-existing-file.txt")
                 .redirectErrorStream(true)
         );
         try {
             process.stdout();
             Assertions.fail("exception expected");
         } catch (final IllegalArgumentException ex) {
             MatcherAssert.assertThat(
                 ex.getMessage(),
                 Matchers.containsString("No such file or directory")
             );
         }
     }
 
     @Test
     void runsACommandLineScriptWithExceptionNoRedir() throws Exception {
         Assumptions.assumeFalse(SystemUtils.IS_OS_WINDOWS, "");
         final VerboseProcess process = new VerboseProcess(
             new ProcessBuilder("cat", "/non-existing-file.txt")
         );
         final VerboseProcess.Result result = process.waitFor();
         MatcherAssert.assertThat(
             result.code(),
             Matchers.equalTo(1)
         );
         MatcherAssert.assertThat(
             result.stderr(),
             Matchers.containsString("No such file or directory")
         );
     }
 
     @Test
     void handlesLongRunningCommand() {
         Assumptions.assumeFalse(SystemUtils.IS_OS_WINDOWS, "");
         final VerboseProcess process = new VerboseProcess(
             new ProcessBuilder("/bin/bash", "-c", "sleep 2; echo 'done'")
         );
         MatcherAssert.assertThat(
             process.stdout(),
             Matchers.startsWith("done")
         );
     }
 
     @Test
     void rejectsNullProcesses() {
         Assertions.assertThrows(
             RuntimeException.class,
             () -> {
                 final ProcessBuilder builder = null;
                 new VerboseProcess(builder);
             }
         );
     }
 
     @Test
     void rejectsStdoutWithLevelAll() {
         try {
             new VerboseProcess(
                 Mockito.mock(Process.class), Level.ALL, Level.INFO
             );
             Assertions.fail("IllegalArgumentException expected");
         } catch (final IllegalArgumentException ex) {
             MatcherAssert.assertThat(
                 ex.getMessage(),
                 Matchers.equalTo(
                     StringUtils.join(
                         "stdout LEVEL can't be set to ALL because it is ",
                         "intended only for internal configuration"
                     )
                 )
             );
         }
     }
 
     @Test
     void rejectsStderrWithLevelAll() {
         try {
             new VerboseProcess(
                 Mockito.mock(Process.class), Level.INFO, Level.ALL
             );
             Assertions.fail("IllegalArgumentException expected here");
         } catch (final IllegalArgumentException ex) {
             MatcherAssert.assertThat(
                 ex.getMessage(),
                 Matchers.equalTo(
                     StringUtils.join(
                         "stderr LEVEL can't be set to ALL because it is ",
                         "intended only for internal configuration"
                     )
                 )
             );
         }
     }
 
     @Test
     @SuppressWarnings("PMD.DoNotUseThreads")
     void quietlyTerminatesLongRunningProcess() throws Exception {
         Assumptions.assumeFalse(SystemUtils.IS_OS_WINDOWS, "");
         final Process proc = new ProcessBuilder("sleep", "10000").start();
         final VerboseProcess process = new VerboseProcess(proc);
         final CountDownLatch start = new CountDownLatch(1);
         final CountDownLatch done = new CountDownLatch(1);
         new Thread(
             new VerboseRunnable(
                 () -> {
                     start.countDown();
                     process.stdoutQuietly();
                     done.countDown();
                 }
             )
         ).start();
         start.await();
         TimeUnit.SECONDS.sleep(1L);
         proc.destroy();
         MatcherAssert.assertThat(
             done.await(1L, TimeUnit.MINUTES),
             Matchers.is(true)
         );
     }
 
     @Test
     void stdoutQuietlyLogsErrors() {
         final StringWriter writer = new StringWriter();
         org.apache.log4j.Logger.getRootLogger().addAppender(
             new WriterAppender(new SimpleLayout(), writer)
         );
         final ProcessBuilder builder;
         final String message = "hello dear friend";
         if (SystemUtils.IS_OS_WINDOWS) {
             builder = new ProcessBuilder("cmd", "/c", "echo", message, "1>&2");
         } else {
             builder = new ProcessBuilder(
                 "cat", String.format("/non-existing-file-%s ", message)
             );
         }
         final VerboseProcess process = new VerboseProcess(
             builder, Level.OFF, Level.WARNING
         );
         process.stdoutQuietly();
         MatcherAssert.assertThat(
             writer.toString(),
             Matchers.containsString(message)
         );
     }
 
     @Test
     @SuppressWarnings("PMD.AvoidFileStream")
     void logsErrorWhenUnderlyingStreamIsClosed() throws Exception {
         final StringWriter writer = new StringWriter();
         org.apache.log4j.Logger.getRootLogger().addAppender(
             new WriterAppender(new SimpleLayout(), writer)
         );
         final Process prc = Mockito.mock(Process.class);
         final Closeable stdout = new FileInputStream(
             File.createTempFile("temp", "test")
         );
         stdout.close();
         Mockito.doReturn(stdout).when(prc).getInputStream();
         Mockito.doReturn(new ByteArrayInputStream(new byte[0]))
             .when(prc).getErrorStream();
         final VerboseProcess process = new VerboseProcess(
             prc,
             Level.FINEST,
             Level.FINEST
         );
         Logger.debug(
             this,
             "#logsErrorWhenUnderlyingStreamIsClosed(): vrbPrc.hashCode=%s",
             process.hashCode()
         );
         process.stdout();
         MatcherAssert.assertThat(
             writer.toString(),
             Matchers.containsString("Error reading from process stream")
         );
     }
 
     @Test
     void terminatesMonitorsAndProcessIfClosedInstantly()
         throws Exception {
         this.terminatesMonitorsAndProcessIfClosed(0L);
     }
 
     @Test
     void terminatesMonitorsAndProcessIfClosedShortly()
         throws Exception {
         this.terminatesMonitorsAndProcessIfClosed(50L);
     }
 
     @Test
     void terminatesMonitorsAndProcessIfClosedNormal() throws Exception {
         final long delay = 400L;
         this.terminatesMonitorsAndProcessIfClosed(delay);
     }
 
     /**
      * VerboseProcess can terminate its monitors and underlying Process if
      * closed after specified time since real usage.
      * @param delay Time in milliseconds between usage of vrbcPrc starts and
      *  its close() issued
      * @throws Exception If something goes wrong
      * @checkstyle ExecutableStatementCountCheck (100 lines)
      */
     private void terminatesMonitorsAndProcessIfClosed(final long delay)
         throws Exception {
         final InputStream input = new VerboseProcessTest.InfiniteInputStream('i');
         final InputStream error = new VerboseProcessTest.InfiniteInputStream('e');
         final Process prc = Mockito.mock(Process.class);
         Mockito.doReturn(input).when(prc).getInputStream();
         Mockito.doReturn(error).when(prc).getErrorStream();
         Mockito.doAnswer(
             invocation -> {
                 input.close();
                 error.close();
                 return null;
             }
         ).when(prc).destroy();
         final VerboseProcess process = new VerboseProcess(
             prc,
             Level.FINEST,
             Level.FINEST
         );
         Logger.debug(
             this,
             "terminatesMntrsAndPrcssIfClosed delay=%d vrbPrc.hashCode=%s",
             delay,
             process.hashCode()
         );
         final StringWriter writer = new StringWriter();
         final WriterAppender appender = new WriterAppender(
             new SimpleLayout(),
             writer
         );
         appender.addFilter(new VerboseProcessTest.VrbPrcMonitorFilter(process));
         org.apache.log4j.Logger.getLogger(
             VerboseProcess.class
         ).addAppender(appender);
         if (delay == 0L) {
             process.close();
         } else {
             new Timer(true).schedule(
                 new TimerTask() {
                     @Override
                     public void run() {
                         process.close();
                     }
                 },
                 delay
             );
         }
         process.stdoutQuietly();
         TimeUnit.MILLISECONDS.sleep(1000L);
         Mockito.verify(
             prc,
             Mockito.atLeastOnce()
         ).destroy();
         MatcherAssert.assertThat(
             writer.toString(),
             Matchers.not(Matchers
                 .containsString("Error reading from process stream")
             )
         );
     }
 
     /**
      * {@link InputStream} returning endless flow of characters.
      *
      * @since 0.1
      */
     private final class InfiniteInputStream extends InputStream {
         /**
          * End of line.
          */
         private static final int LINE_FEED = 0xA;
 
         /**
          * Character, endlessly repeated in the stream.
          */
         private final transient char chr;
 
         /**
          * Whether the next char in the stream should be EOL.
          */
         private transient boolean feed;
 
         /**
          * Whether this stream is closed.
          */
         private transient boolean closed;
 
         /**
          * Construct an InputStream returning endless combination of this
          * character and end of line.
          * @param character Character to return in the stream
          */
         InfiniteInputStream(final char character) {
             super();
             this.chr = character;
         }
 
         @Override
         public int read() throws IOException {
             if (this.closed) {
                 throw new IOException("Stream closed");
             }
             final int next;
             if (this.feed) {
                 this.feed = false;
                 next = VerboseProcessTest.InfiniteInputStream.LINE_FEED;
             } else {
                 this.feed = true;
                 next = this.chr;
             }
             return next;
         }
 
         @Override
         public void close() {
             this.closed = true;
         }
     }
 
     /**
      * Filter of log messages of {@link VerboseProcess}'s monitor threads.
      *
      * <p>It filters out messages of monitor threads, that doesn't belong to
      * specific {@link VerboseProcess}.
      *
      * @since 0.1
      */
     private final class VrbPrcMonitorFilter extends Filter {
         /**
          * Monitor's log message start.
          */
         private static final String THREADNAME_START = "VrbPrc.Monitor-";
 
         /**
          * HashCode of {@link VerboseProcess} to filter.
          */
         private final transient int hash;
 
         /**
          * Create filter for this process.
          *
          * <p>The messages from its monitor threads will be filtered in.
          * @param prc Process
          */
         VrbPrcMonitorFilter(final VerboseProcess prc) {
             super();
             this.hash = prc.hashCode();
         }
 
         @Override
         public int decide(final LoggingEvent event) {
             final String thread = event.getThreadName();
             final int decision;
             if (thread.startsWith(VerboseProcessTest.VrbPrcMonitorFilter.THREADNAME_START
                 + this.hash
             )) {
                 decision = Filter.ACCEPT;
             } else {
                 decision = Filter.DENY;
             }
             return decision;
         }
     }
 }