assertEquals("", Strings.commonPrefix("xyz", "abcde"));
    assertEquals("", Strings.commonPrefix("xyz", "abcxyz"));
    assertEquals("a", Strings.commonPrefix("abc", "aaaaa"));
    assertEquals("aa", Strings.commonPrefix("aa", "aaaaa"));
    assertEquals("abc", Strings.commonPrefix(new StringBuilder("abcdef"), "abcxyz"));

    // Identical valid surrogate pairs.
    assertEquals(

    assertEquals("", Strings.commonPrefix("xyz", "abcde"));
    assertEquals("", Strings.commonPrefix("xyz", "abcxyz"));
    assertEquals("a", Strings.commonPrefix("abc", "aaaaa"));
    assertEquals("aa", Strings.commonPrefix("aa", "aaaaa"));
    assertEquals("abc", Strings.commonPrefix(new StringBuilder("abcdef"), "abcxyz"));

    // Identical valid surrogate pairs.
    assertEquals(

  static final String LOTS_OF_DELTAS = Strings.repeat(DELTA, 62);

  private static final String ALMOST_TOO_MANY_LEVELS = Strings.repeat("a.", 127);

  private static final String ALMOST_TOO_LONG = Strings.repeat("aaaaa.", 40) + "1234567890.c";

  private static final ImmutableSet<String> VALID_NAME =
      ImmutableSet.of(
          "foo.com",
          "f-_-o.cOM",
          "f--1.com",
          "f11-1.com",
          "www",

AuB,YAQhE/G,EAAAA,QAAEC,GAAGJ,GAAQ6H,EAAejE,iBAC5BzD,EAAAA,QAAEC,GAAGJ,GAAMqE,YAAcwD,EACzB1H,EAAAA,QAAEC,GAAGJ,GAAMsE,WAAa,WAEtB,OADAnE,EAAAA,QAAEC,GAAGJ,GAAQE,EACN2H,EAAejE,kBC9TxB,IAAM5D,EAAO,aACPC,EAAW,iBAEXC,EAAqBC,EAAAA,QAAEC,GAAGJ,GAc1BwK,EAAAA,WACJ,SAAAA,EAAY7I,GACVE,KAAKC,SAAWH,qBAGlBqE,OAAA,WACE7F,EAAAA,QAAE0B,KAAKC,UAAUE,QAfQ,gBAesBC,QAAQwI,YAbvB,6BAchCtK,EAAAA,QAAE0B,KAAKC,UAAUnB,QAAQR,EAAAA,QAAEoD,MAnBZ,8BAwBVK,iBAAP,SAAwBC,GACtB,OAAOhC,KAAKuC,MAAK,WACf,IAAIN,EAAO3D,EAAAA,QAAE0B,MAAM...

AAsB,iBAC1BoI,GAAI,CAACnO,EAAS,cAAeA,EAAS,WACtCjF,EAAG,CAAC,aAAc,YAClBqT,GAAI,CAACpO,EAAS,YAAaA,EAAS,WACpCqO,EAAG,CAAC,YAAa,UACjBC,GAAI,CAACtO,EAAS,WAAYA,EAAS,UACnC8K,EAAG,CAAC,YAAa,UACjByD,GAAI,CAACvO,EAAS,WAAYA,EAAS,QACnC0O,EAAG,CAAC,eAAgB,aACpBC,GAAI,CAAC3O,EAAS,cAAeA,EAAS,WACtC2I,EAAG,CAAC,aAAc,YAClBiG,GAAI,CAAC5O,EAAS,YAAaA,EAAS,YAExC,OAAOklB,EAAWzqB,EAAOqE,GAAK,GAAKrE,EAAOqE,GAAK,GAnQnDtG,EAAM0X,aAAa,KAAM,CACrBhJ,OAzCW,CACP,gBACA,aACA,aACA,aACA,gBACA,kBACA,cACA,iBACA,eACA,gBACA,eACA,mBA8BJ...

,EAAmBhN,GAC3B,OAAO,SAAU8B,GAChB,OAAOD,GAAUC,EAAM,UAAaA,EAAK9B,OAASA,GAQpD,SAASiN,EAAoBjN,GAC5B,OAAO,SAAU8B,GAChB,OAASD,GAAUC,EAAM,UAAaD,GAAUC,EAAM,YACrDA,EAAK9B,OAASA,GAQjB,SAASkN,EAAsBtC,GAG9B,OAAO,SAAU9I,GAKhB,MAAK,SAAUA,EASTA,EAAKb,aAAgC,IAAlBa,EAAK8I,SAGvB,UAAW9I,EACV,UAAWA,EAAKb,WACba,EAAKb,WAAW2J,WAAaA,EAE7B9I,EAAK8I,WAAaA,EAMpB9I,EAAKqL,aAAevC,GAG1B9I,EAAKqL,cAAgBvC,GACpBF,EAAoB5I,KAAW8I,EAG3B9I,EAAK8I,WAAaA,EAKd,UAAW9I,GACfA,EAAK8I,WAAaA,GAY5B,SAASwC,EAAwB3L,GAChC,OAAOoL,EAAc,SAAUQ,GAE9...

UL,MACVM,MAAQJ,MACRK,OAASL,MCRhB,eAAqD,IAC7CM,GAAiB,GAATC,KAAe,MAAfA,CAAwB,MAChCC,EAAkB,MAAVF,IAAmB,OAAnBA,CAA6B,eAGzCG,YAAWC,oBAAAA,CAAXD,EACAA,WAAWC,oBAAAA,CAAXD,qBCd8C,OACzCE,IACLzD,YAAAA,CADKyD,CAELzD,YAAAA,CAFKyD,CAGLhB,YAAAA,CAHKgB,CAILhB,YAAAA,CAJKgB,CAKLhB,YAAAA,CALKgB,CAML3C,EAAK,EAALA,EACK4C,SAASjB,YAAAA,CAATiB,EACHA,SAASC,YAAgC,QAATN,KAAoB,KAApBA,CAA4B,OAAnDM,CAATD,CADGA,CAEHA,SAASC,YAAgC,QAATN,KAAoB,QAApBA,CAA+B,QAAtDM,CAATD,CAHF5C,CAIE,CAVG2C,EAcT,aAAiD,IACzCzD,GAAOD,EAASC,KAChByC,E...

,EAAmBhN,GAC3B,OAAO,SAAU8B,GAChB,OAAOD,GAAUC,EAAM,UAAaA,EAAK9B,OAASA,GAQpD,SAASiN,EAAoBjN,GAC5B,OAAO,SAAU8B,GAChB,OAASD,GAAUC,EAAM,UAAaD,GAAUC,EAAM,YACrDA,EAAK9B,OAASA,GAQjB,SAASkN,EAAsBtC,GAG9B,OAAO,SAAU9I,GAKhB,MAAK,SAAUA,EASTA,EAAKb,aAAgC,IAAlBa,EAAK8I,SAGvB,UAAW9I,EACV,UAAWA,EAAKb,WACba,EAAKb,WAAW2J,WAAaA,EAE7B9I,EAAK8I,WAAaA,EAMpB9I,EAAKqL,aAAevC,GAG1B9I,EAAKqL,cAAgBvC,GACpBF,EAAoB5I,KAAW8I,EAG3B9I,EAAK8I,WAAaA,EAKd,UAAW9I,GACfA,EAAK8I,WAAaA,GAY5B,SAASwC,EAAwB3L,GAChC,OAAOoL,EAAc,SAAUQ,GAE9...

SuF,QAAQ,UAAUgB,GAAG,gBAAiB5C,KAAKwd,mBAEvDxd,KAAKhC,OAAO1B,SACd0D,KAAKhC,OACAsS,EAAA,GAAAtQ,KAAKhC,OADV,CAEER,QAAS,SACTlB,SAAU,KAGZ0D,KAAKuf,aAITA,YAAA,WACE,IAAMC,SAAmBxf,KAAK3D,QAAQE,aAAa,wBAE/CyD,KAAK3D,QAAQE,aAAa,UAA0B,WAAdijB,KACxCxf,KAAK3D,QAAQ2H,aACX,sBACAhE,KAAK3D,QAAQE,aAAa,UAAY,IAGxCyD,KAAK3D,QAAQ2H,aAAa,QAAS,MAIvCqZ,SAAA,SAAOjd,EAAO+Q,GACZ,IAAM8L,EAAUjd,KAAKuQ,YAAYxP,UACjCoQ,EAAUA,GAAWrU,UAAEsD,EAAMyN,eAAerL,KAAKya,MAG/C9L,EAAU,IAAInR,KAAKuQ,YACjBnQ,EAAMyN,cACN7N,KAAKkd,sBAEPpgB,UAAEs...

,UACE,iBAAA,eAGF,gBACE,iBAAA,sBCXF,QAAkB,OAAA,IAAA,MAAA,kBAClB,YAAkB,WAAA,IAAA,MAAA,kBAClB,cAAkB,aAAA,IAAA,MAAA,kBAClB,eAAkB,cAAA,IAAA,MAAA,kBAClB,aAAkB,YAAA,IAAA,MAAA,kBAElB,UAAmB,OAAA,YACnB,cAAmB,WAAA,YACnB,gBAAmB,aAAA,YACnB,iBAAmB,cAAA,YACnB,eAAmB,YAAA,YAGjB,gBACE,aAAA,kBADF,kBACE,aAAA,kBADF,gBACE,aAAA,kBADF,aACE,aAAA,kBADF,gBACE,aAAA,kBADF,eACE,aAAA,kBADF,cACE,aAAA,kBADF,aACE,aAAA,kBAIJ,cACE,aAAA,eAOF,YACE,cAAA,gBAGF,SACE,cAAA,iBAGF,aACE,uBAAA,iBACA,wBAAA,iBAGF,eACE,wBAAA,iBACA,2BAAA,iBAGF,g...