code: package com.beijunyi.parallelgit.filesystem;
  
  import java.io.IOException;
  import java.nio.file.Files;
  
  import org.junit.Before;
  import org.junit.Test;
  
  import static org.junit.Assert.*;
  
  public class FilesIsHiddenTest extends AbstractGitFileSystemTest {
  
    @Before
    public void setupFileSystem() throws IOException {
      initGitFileSystem();
    }
  
    @Test
    public void rootIsHiddenTest() throws IOException {
      assertFalse(Files.isHidden(gfs.getRootPath()));
    }
  
    @Test
    public void commonFilePathIsHiddenTest() throws IOException {
      assertFalse(Files.isHidden(gfs.getPath("file.txt")));
      assertFalse(Files.isHidden(gfs.getPath("/file.txt")));
    }
  
    @Test
    public void pathWithNoExtensionIsHiddenTest() throws IOException {
      assertFalse(Files.isHidden(gfs.getPath("file")));
      assertFalse(Files.isHidden(gfs.getPath("/file")));
    }
  
    @Test
    public void pathWithDotIsHiddenTest() throws IOException {
      assertFalse(Files.isHidden(gfs.getPath(".")));
      assertFalse(Files.isHidden(gfs.getPath("/.")));
      assertFalse(Files.isHidden(gfs.getPath("dir/.")));
      assertFalse(Files.isHidden(gfs.getPath("/dir/.")));
    }
  
    @Test
    public void pathWithDoubleDotsIsHiddenTest() throws IOException {
      assertFalse(Files.isHidden(gfs.getPath("..")));
      assertFalse(Files.isHidden(gfs.getPath("/..")));
      assertFalse(Files.isHidden(gfs.getPath("dir/..")));
      assertFalse(Files.isHidden(gfs.getPath("/dir/..")));
    }
  
    @Test
    public void pathWithFilenameStartingWithDotIsHiddenTest() throws IOException {
      assertTrue(Files.isHidden(gfs.getPath(".file")));
      assertTrue(Files.isHidden(gfs.getPath("/.file")));
      assertTrue(Files.isHidden(gfs.getPath(".file.txt")));
      assertTrue(Files.isHidden(gfs.getPath("/.file.txt")));
      assertTrue(Files.isHidden(gfs.getPath("dir/.file.txt")));
      assertTrue(Files.isHidden(gfs.getPath("/dir/.file.txt")));
      assertTrue(Files.isHidden(gfs.getPath("dir/../.file.txt")));
      assertTrue(Files.isHidden(gfs.getPath("/dir/../.file.txt")));
    }
  }
  