### Question:
ExecUtils { public static boolean isLinux() { return isLinux(System.getProperty("os.name")); }  static File find(String executable, File... dirs); static File findExecutableInDirectory(String executable, File directory); static File findExecutableInSystemPath(String executable); static boolean isWindows(); static boolean isWindows(String os); static boolean isMac(); static boolean isMac(String os); static boolean isLinux(); static boolean isLinux(String os); static boolean is64bits(); static boolean is64bits(String arch); static boolean isARM();  }### Answer:
@Test public void testIsLinux() throws Exception { assertThat(ExecUtils.isLinux( "Microsoft Windows 3.1")).isFalse(); assertThat(ExecUtils.isLinux("Linux")).isTrue(); assertThat(ExecUtils.isLinux("AIX")).isTrue(); assertThat(ExecUtils.isLinux("Digital Unix")).isTrue(); }