### Question:
File { final boolean isRootDirectory() { return isDirectory() && equals(((Directory) this).parent()); } File(int id); int id(); long size(); final boolean isDirectory(); final boolean isRegularFile(); final boolean isSymbolicLink(); final synchronized int links(); @SuppressWarnings("GoodTime") // should return a java.time.Instant final synchronized long getCreationTime(); @SuppressWarnings("GoodTime") // should return a java.time.Instant final synchronized long getLastAccessTime(); @SuppressWarnings("GoodTime") // should return a java.time.Instant final synchronized long getLastModifiedTime(); final synchronized ImmutableSet<String> getAttributeNames(String view); @NullableDecl final synchronized Object getAttribute(String view, String attribute); final synchronized void setAttribute(String view, String attribute, Object value); final synchronized void deleteAttribute(String view, String attribute); @Override final String toString();  }### Answer:
@Test public void testRootDirectory() { Directory file = Directory.createRoot(0, Name.simple("/")); assertThat(file.isRootDirectory()).isTrue(); Directory otherFile = Directory.createRoot(1, Name.simple("$")); assertThat(otherFile.isRootDirectory()).isTrue(); }