### Question:
DefaultDirectoryWriter implements DirectoryWriter { @Override public String toHtml( @NotNull final File directory, @URL final String requestURL, final boolean includeParent ) throws IOException { final Directory dir = this.getDirectory(directory, requestURL, includeParent); return directoryToHTML(directory.getName(), dir); }  static String directoryToHTML(final String directoryName, final Directory directory); @Override String toHtml(
        @NotNull final File directory,
        @URL final String requestURL,
        final boolean includeParent
    ); @Override String toJson(
        @NotNull final File directory,
        @URL final String requestURL,
        final boolean includeParent
    );  }### Answer:
@Test void canConvertToHtml() throws Exception { this.setupWithParent(); final String html = this.writer.toHtml(this.directory, REQUEST_URL_WITH_PARENT, true); Assertions.assertThat(html).isNotNull(); final Tidy tidy = new Tidy(); final Writer stringWriter = new StringWriter(); tidy.parse(new ByteArrayInputStream(html.getBytes(StandardCharsets.UTF_8)), stringWriter); Assertions.assertThat(tidy.getParseErrors()).isEqualTo(0); Assertions.assertThat(tidy.getParseWarnings()).isEqualTo(0); }