@CanIgnoreReturnValue
  public PathSubject isSameFileAs(Path path) throws IOException {
    if (!Files.isSameFile(actual, path)) {
      failWithActual("expected to be same file as", path);
    }
    return this;
  }
Asserts that the path resolves to the same file as the given path.
jimfs/src/test/java/com/google/common/jimfs/PathSubject.java