### Question:
OperatingSystemUtils { public static File createTempDir() throws IllegalStateException { File baseDir = getTempDirectory(); try { return Files.createTempDirectory(baseDir.toPath(), "tmpdir").toFile(); } catch (IOException e) { throw new IllegalStateException("Error while creating temporary directory", e); } }  static String getOsName(); static boolean isWindows(); static boolean isOSX(); static boolean isLinux(); static File getWorkingDir(); static File getForgeHomeDir(); static File getUserHomeDir(); static String getUserHomePath(); static File getUserForgeDir(); static void setPretendWindows(boolean value); static String getLineSeparator(); static String getSafeFilename(String filename); static File createTempDir(); static File getTempDirectory(); static boolean isJava8();  }### Answer:
@Test public void testCreateTempDir() { File tmpDir = OperatingSystemUtils.createTempDir(); tmpDir.deleteOnExit(); Assert.assertThat(tmpDir.isDirectory(), is(true)); }