*
 * <p>{@link java.nio.file.Path} users will find similar utilities in {@link MoreFiles} and the
 * JDK's {@link java.nio.file.Files} class.
 *
 * @author Chris Nokleberg
 * @author Colin Decker
 * @since 1.0
 */
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
public final class Files {

  private Files() {}

  /**

/**
 * Unit test for {@link Files#createTempDir}.
 *
 * @author Chris Nokleberg
 */

@SuppressWarnings("deprecation") // tests of a deprecated method
public class FilesCreateTempDirTest extends TestCase {
  public void testCreateTempDir() throws IOException {
    if (JAVA_IO_TMPDIR.value().equals("/sdcard")) {
      assertThrows(IllegalStateException.class, Files::createTempDir);
      return;
    }

    assertEquals("gz", Files.getFileExtension("blah.tar.gz"));
    assertEquals("", Files.getFileExtension("/"));
    assertEquals("", Files.getFileExtension("."));
    assertEquals("", Files.getFileExtension(".."));
    assertEquals("", Files.getFileExtension("..."));
    assertEquals("", Files.getFileExtension("blah"));
    assertEquals("", Files.getFileExtension("blah."));
    assertEquals("", Files.getFileExtension(".blah."));

                .build());
    Files.createDirectories(fs.getPath("dir/b/i/j/l"));
    Files.createFile(fs.getPath("dir/a"));
    Files.createFile(fs.getPath("dir/c"));
    Files.createSymbolicLink(fs.getPath("dir/d"), fs.getPath("b/i"));
    Files.createDirectory(fs.getPath("dir/e"));
    Files.createSymbolicLink(fs.getPath("dir/f"), fs.getPath("/dontdelete"));
    Files.createFile(fs.getPath("dir/b/g"));

import java.io.IOException;

/**
 * Tests for {@link Files#fileTraverser()}.
 *
 * @author Jens Nyman
 */

public class FilesFileTraverserTest extends IoTestCase {

  private File rootDir;

  @Override
  public void setUp() throws IOException {
    rootDir = createTempDir();
  }

  public void testFileTraverser_emptyDirectory() throws Exception {

    assertEquals("gz", Files.getFileExtension("blah.tar.gz"));
    assertEquals("", Files.getFileExtension("/"));
    assertEquals("", Files.getFileExtension("."));
    assertEquals("", Files.getFileExtension(".."));
    assertEquals("", Files.getFileExtension("..."));
    assertEquals("", Files.getFileExtension("blah"));
    assertEquals("", Files.getFileExtension("blah."));
    assertEquals("", Files.getFileExtension(".blah."));

 * identical to the original.
 *
 * @author Chris Povirk
 */
/*
 * The whole thing is really @GwtIncompatible, but GwtJUnitConvertedTestModule doesn't have a
 * parameter for non-GWT, non-test files, and it didn't seem worth adding one for this unusual case.
 */
@GwtCompatible(emulated = true)
final class LenientSerializableTester {
  /*

import com.google.common.base.Preconditions;
import java.io.File;
import java.io.FilenameFilter;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;

/**
 * File name filter that only accepts files matching a regular expression. This class is thread-safe
 * and immutable.
 *
 * @author Apple Chow
 * @since 1.0
 */
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault

    private static final String MESSAGE =
        "Guava cannot securely create temporary files or directories under SDK versions before"
            + " Jelly Bean. You can create one yourself, either in the insecure default directory"
            + " or in a more secure directory, such as context.getCacheDir(). For more information,"
            + " see the Javadoc for Files.createTempDir().";

    @Override
    File createTempDir() {

        FileOutputStream out = new FileOutputStream(file);
        try {
          out.write(initialBytes);
        } finally {
          out.close();
        }
        return Files.asByteSink(file, FileWriteMode.APPEND);
      }
      return Files.asByteSink(file);
    }

    @Override
    public byte[] getExpected(byte[] bytes) {
      if (initialBytes == null) {
        return checkNotNull(bytes);
      } else {