mcs/class/System/Test/System.Net/DnsTest.cs

   1 // DnsTest.cs - NUnit Test Cases for the System.Net.Dns class\r
   2 //\r
   3 // Authors: \r
   4 //   Mads Pultz (mpultz@diku.dk)\r
   5 //   Martin Willemoes Hansen (mwh@sysrq.dk)\r
   6 //\r
   7 // (C) 2001 Mads Pultz\r
   8 // (C) 2003 Martin Willemoes Hansen\r
   9 // \r
  10 // This test assumes the following:\r
  11 // 1) The following Internet sites exist:\r
  12 //        www.go-mono.com with IP address 64.14.94.188\r
  13 //        info.diku.dk with IP address 130.225.96.4\r
  14 // 2) The following DNS name does not exist:\r
  15 //        www.hopefullydoesnotexist.dk\r
  16 //\r
  17 \r
  18 using System;\r
  19 using System.Collections;\r
  20 using System.Net;\r
  21 using System.Net.Sockets;\r
  22 using System.Threading;\r
  23 \r
  24 using NUnit.Framework;\r
  25 \r
  26 namespace MonoTests.System.Net\r
  27 {\r
  28         [TestFixture]\r
  29         public class DnsTest\r
  30         {\r
  31                 private String site1Name = "mono-project.com",\r
  32                         site1Dot = "96.126.105.110",\r
  33                         site2Name = "info.diku.dk",\r
  34                         site2Dot = "130.225.96.4",\r
  35                         noneExistingSite = "www.unlikely.novell.com";\r
  36                 private uint site1IP = 1852407392, site2IP = 2195808260; // Big-Endian\r
  37 \r
  38                 [Test]\r
  39                 public void AsyncGetHostByName ()\r
  40                 {\r
  41                         IAsyncResult r;\r
  42                         r = Dns.BeginGetHostByName (site1Name, new AsyncCallback (GetHostByNameCallback), null);\r
  43 \r
  44                         IAsyncResult async = Dns.BeginGetHostByName (site1Name, null, null);\r
  45                         IPHostEntry entry = Dns.EndGetHostByName (async);\r
  46                         SubTestValidIPHostEntry (entry);\r
  47                         Assert.AreEqual ("www.mono-project.com", entry.HostName);\r
  48                 }\r
  49 \r
  50                 void GetHostByNameCallback (IAsyncResult ar)\r
  51                 {\r
  52                         IPHostEntry h;\r
  53                         h = Dns.EndGetHostByName (ar);\r
  54                         SubTestValidIPHostEntry (h);\r
  55                 }\r
  56 \r
  57                 [Test]\r
  58                 public void AsyncResolve ()\r
  59                 {\r
  60                         IAsyncResult r;\r
  61                         r = Dns.BeginResolve (site1Name, new AsyncCallback (ResolveCallback), null);\r
  62 \r
  63                         IAsyncResult async = Dns.BeginResolve (site1Dot, null, null);\r
  64                         IPHostEntry entry = Dns.EndResolve (async);\r
  65                         SubTestValidIPHostEntry (entry);\r
  66                         Assert.AreEqual (site1Dot, entry.AddressList [0].ToString ());\r
  67                 }\r
  68 \r
  69                 void ResolveCallback (IAsyncResult ar)\r
  70                 {\r
  71                         IPHostEntry h = Dns.EndResolve (ar);\r
  72                         SubTestValidIPHostEntry (h);\r
  73                 }\r
  74 \r
  75 #if NET_2_0\r
  76                 [Test]\r
  77                 public void BeginGetHostAddresses_HostNameOrAddress_Null ()\r
  78                 {\r
  79                         try {\r
  80                                 Dns.BeginGetHostAddresses (\r
  81                                         (string) null,\r
  82                                         new AsyncCallback (GetHostAddressesCallback),\r
  83                                         null);\r
  84                                 Assert.Fail ("#1");\r
  85                         } catch (ArgumentNullException ex) {\r
  86                                 Assert.AreEqual (typeof (ArgumentNullException), ex.GetType (), "#2");\r
  87                                 Assert.IsNull (ex.InnerException, "#3");\r
  88                                 Assert.IsNotNull (ex.Message, "#4");\r
  89                                 Assert.AreEqual ("hostName", ex.ParamName, "#5");\r
  90                         }\r
  91                 }\r
  92 \r
  93                 [Test]\r
  94                 public void BeginGetHostAddresses_HostNameOrAddress_UnspecifiedAddress ()\r
  95                 {\r
  96                         // IPv4\r
  97                         try {\r
  98                                 Dns.BeginGetHostAddresses (\r
  99                                         "0.0.0.0",\r
 100                                         new AsyncCallback (GetHostAddressesCallback),\r
 101                                         null);\r
 102                                 Assert.Fail ("#A1");\r
 103                         } catch (ArgumentException ex) {\r
 104                                 // IPv4 address 0.0.0.0 and IPv6 address ::0 are\r
 105                                 // unspecified addresses that cannot be used as\r
 106                                 // a target address\r
 107                                 Assert.AreEqual (typeof (ArgumentException), ex.GetType (), "#A2");\r
 108                                 Assert.IsNull (ex.InnerException, "#A3");\r
 109                                 Assert.IsNotNull (ex.Message, "#A4");\r
 110                                 Assert.AreEqual ("hostNameOrAddress", ex.ParamName, "#A5");\r
 111                         }\r
 112 \r
 113                         // IPv6\r
 114                         try {\r
 115                                 Dns.BeginGetHostAddresses (\r
 116                                         "::0",\r
 117                                         new AsyncCallback (GetHostAddressesCallback),\r
 118                                         null);\r
 119                                 Assert.Fail ("#B1");\r
 120                         } catch (ArgumentException ex) {\r
 121                                 // IPv4 address 0.0.0.0 and IPv6 address ::0 are\r
 122                                 // unspecified addresses that cannot be used as\r
 123                                 // a target address\r
 124                                 Assert.AreEqual (typeof (ArgumentException), ex.GetType (), "#B2");\r
 125                                 Assert.IsNull (ex.InnerException, "#B3");\r
 126                                 Assert.IsNotNull (ex.Message, "#B4");\r
 127                                 Assert.AreEqual ("hostNameOrAddress", ex.ParamName, "#B5");\r
 128                         }\r
 129                 }\r
 130 \r
 131                 void GetHostAddressesCallback (IAsyncResult ar)\r
 132                 {\r
 133                         IPAddress [] addresses = Dns.EndGetHostAddresses (ar);\r
 134                         Assert.IsNotNull (addresses);\r
 135                 }\r
 136 \r
 137                 [Test]\r
 138                 public void GetHostAddresses_HostNameOrAddress_Null ()\r
 139                 {\r
 140                         try {\r
 141                                 Dns.GetHostAddresses ((string) null);\r
 142                                 Assert.Fail ("#1");\r
 143                         } catch (ArgumentNullException ex) {\r
 144                                 Assert.AreEqual (typeof (ArgumentNullException), ex.GetType (), "#2");\r
 145                                 Assert.IsNull (ex.InnerException, "#3");\r
 146                                 Assert.IsNotNull (ex.Message, "#4");\r
 147                                 Assert.AreEqual ("hostNameOrAddress", ex.ParamName, "#5");\r
 148                         }\r
 149                 }\r
 150 \r
 151                 [Test]\r
 152                 public void GetHostAddresses_HostNameOrAddress_UnspecifiedAddress ()\r
 153                 {\r
 154                         // IPv4\r
 155                         try {\r
 156                                 Dns.GetHostAddresses ("0.0.0.0");\r
 157                                 Assert.Fail ("#A1");\r
 158                         } catch (ArgumentException ex) {\r
 159                                 // IPv4 address 0.0.0.0 and IPv6 address ::0 are\r
 160                                 // unspecified addresses that cannot be used as\r
 161                                 // a target address\r
 162                                 Assert.AreEqual (typeof (ArgumentException), ex.GetType (), "#A2");\r
 163                                 Assert.IsNull (ex.InnerException, "#A3");\r
 164                                 Assert.IsNotNull (ex.Message, "#A4");\r
 165                                 Assert.AreEqual ("hostNameOrAddress", ex.ParamName, "#A5");\r
 166                         }\r
 167 \r
 168                         // IPv6\r
 169                         try {\r
 170                                 Dns.GetHostAddresses ("::0");\r
 171                                 Assert.Fail ("#B1");\r
 172                         } catch (ArgumentException ex) {\r
 173                                 // IPv4 address 0.0.0.0 and IPv6 address ::0 are\r
 174                                 // unspecified addresses that cannot be used as\r
 175                                 // a target address\r
 176                                 Assert.AreEqual (typeof (ArgumentException), ex.GetType (), "#B2");\r
 177                                 Assert.IsNull (ex.InnerException, "#B3");\r
 178                                 Assert.IsNotNull (ex.Message, "#B4");\r
 179                                 Assert.AreEqual ("hostNameOrAddress", ex.ParamName, "#B5");\r
 180                         }\r
 181                 }\r
 182 #endif\r
 183 \r
 184                 [Test]\r
 185                 public void GetHostName ()\r
 186                 {\r
 187                         string hostName = Dns.GetHostName ();\r
 188                         Assert.IsNotNull (hostName);\r
 189                 }\r
 190 \r
 191                 [Test]\r
 192                 public void GetHostByName ()\r
 193                 {\r
 194                         SubTestGetHostByName ("www.mono-project.com", site1Dot);\r
 195                         SubTestGetHostByName (site2Name, site2Dot);\r
 196                         try {\r
 197                                 var entry = Dns.GetHostByName (noneExistingSite);\r
 198                                 /*\r
 199                                  * Work around broken t-online.de DNS Server.\r
 200                                  * \r
 201                                  * T-Online's DNS Server for DSL Customers resolves\r
 202                                  * non-exisitng domain names to\r
 203                                  * http://navigationshilfe1.t-online.de/dnserror?url=....\r
 204                                  * instead of reporting an error.\r
 205                                  */\r
 206                                 var navigationshilfe1 = IPAddress.Parse ("80.156.86.78");\r
 207                                 var navigationshilfe2 = IPAddress.Parse ("62.157.140.133");\r
 208                                 foreach (var addr in entry.AddressList) {\r
 209                                         if (addr.Equals (navigationshilfe1) || addr.Equals (navigationshilfe2))\r
 210                                                 return;\r
 211                                 }\r
 212                                 Assert.Fail ("Should raise a SocketException (assuming that '" + noneExistingSite + "' does not exist)");\r
 213                         } catch (SocketException) {\r
 214                         }\r
 215                 }\r
 216 \r
 217                 void SubTestGetHostByName (string siteName, string siteDot)\r
 218                 {\r
 219                         IPHostEntry h = Dns.GetHostByName (siteName);\r
 220                         SubTestValidIPHostEntry (h);\r
 221                         Assert.AreEqual (siteName, h.HostName, "siteName");\r
 222                         Assert.AreEqual (siteDot, h.AddressList [0].ToString (), "siteDot");\r
 223                 }\r
 224 \r
 225                 [Test]\r
 226                 public void GetHostByName_HostName_Null ()\r
 227                 {\r
 228                         try {\r
 229                                 Dns.GetHostByName ((string) null);\r
 230                                 Assert.Fail ("#1");\r
 231                         } catch (ArgumentNullException ex) {\r
 232                                 Assert.AreEqual (typeof (ArgumentNullException), ex.GetType (), "#2");\r
 233                                 Assert.IsNull (ex.InnerException, "#3");\r
 234                                 Assert.IsNotNull (ex.Message, "#4");\r
 235                                 Assert.AreEqual ("hostName", ex.ParamName, "#5");\r
 236                         }\r
 237                 }\r
 238 \r
 239                 [Test]\r
 240                 public void GetHostByAddressString_Address_Null ()\r
 241                 {\r
 242                         try {\r
 243                                 Dns.GetHostByAddress ((string) null);\r
 244                                 Assert.Fail ("#1");\r
 245                         } catch (ArgumentNullException ex) {\r
 246                                 Assert.AreEqual (typeof (ArgumentNullException), ex.GetType (), "#2");\r
 247                                 Assert.IsNull (ex.InnerException, "#3");\r
 248                                 Assert.IsNotNull (ex.Message, "#4");\r
 249                                 Assert.AreEqual ("address", ex.ParamName, "#5");\r
 250                         }\r
 251                 }\r
 252 \r
 253                 [Test]\r
 254                 [ExpectedException (typeof (SocketException))]\r
 255 #if TARGET_JVM\r
 256                 [Ignore ("Ignore failures in Sys.Net")]\r
 257 #endif\r
 258                 public void GetHostByAddressString2 ()\r
 259                 {\r
 260                         Dns.GetHostByAddress ("123.255.23");\r
 261                 }\r
 262 \r
 263                 [Test]\r
 264                 [ExpectedException (typeof (FormatException))]\r
 265                 public void GetHostByAddressString3 ()\r
 266                 {\r
 267                         Dns.GetHostByAddress ("123.256.34.10");\r
 268                 }\r
 269 \r
 270                 [Test, ExpectedException (typeof (FormatException))]\r
 271                 public void GetHostByAddressString4 ()\r
 272                 {\r
 273                         Dns.GetHostByAddress ("not an IP address");\r
 274                 }\r
 275 \r
 276                 [Test]\r
 277                 public void GetHostByAddressString5 ()\r
 278                 {\r
 279                         Dns.GetHostByAddress (site1Dot);\r
 280                 }\r
 281 \r
 282                 [Test]\r
 283                 public void GetHostByAddressIPAddress_Address_Null ()\r
 284                 {\r
 285                         try {\r
 286                                 Dns.GetHostByAddress ((IPAddress) null);\r
 287                                 Assert.Fail ("#1");\r
 288                         } catch (ArgumentNullException ex) {\r
 289                                 Assert.AreEqual (typeof (ArgumentNullException), ex.GetType (), "#2");\r
 290                                 Assert.IsNull (ex.InnerException, "#3");\r
 291                                 Assert.IsNotNull (ex.Message, "#4");\r
 292                                 Assert.AreEqual ("address", ex.ParamName, "#5");\r
 293                         }\r
 294                 }\r
 295 \r
 296                 [Test]\r
 297                 public void GetHostByAddressIPAddress2 ()\r
 298                 {\r
 299                         IPAddress addr = new IPAddress (IPAddress.NetworkToHostOrder ((int) site1IP));\r
 300                         IPHostEntry h = Dns.GetHostByAddress (addr);\r
 301                         SubTestValidIPHostEntry (h);\r
 302                         Assert.AreEqual (addr.ToString (), h.AddressList [0].ToString ());\r
 303                 }\r
 304 \r
 305                 [Test]\r
 306                 public void GetHostByAddressIPAddress3 ()\r
 307                 {\r
 308                         IPAddress addr = new IPAddress (IPAddress.NetworkToHostOrder ((int) site2IP));\r
 309                         IPHostEntry h = Dns.GetHostByAddress (addr);\r
 310                         SubTestValidIPHostEntry (h);\r
 311                         Assert.AreEqual (addr.ToString (), h.AddressList [0].ToString ());\r
 312                 }\r
 313 \r
 314                 [Test]\r
 315                 public void BeginResolve_HostName_Null ()\r
 316                 {\r
 317                         try {\r
 318                                 Dns.BeginResolve ((string) null,\r
 319                                         new AsyncCallback (ResolveCallback),\r
 320                                         null);\r
 321                                 Assert.Fail ("#1");\r
 322                         } catch (ArgumentNullException ex) {\r
 323                                 Assert.AreEqual (typeof (ArgumentNullException), ex.GetType (), "#2");\r
 324                                 Assert.IsNull (ex.InnerException, "#3");\r
 325                                 Assert.IsNotNull (ex.Message, "#4");\r
 326                                 Assert.AreEqual ("hostName", ex.ParamName, "#5");\r
 327                         }\r
 328                 }\r
 329 \r
 330                 [Test]\r
 331                 public void Resolve ()\r
 332                 {\r
 333                         SubTestResolve (site1Name);\r
 334                         SubTestResolve (site2Name);\r
 335                         SubTestResolve (site1Dot);\r
 336                         SubTestResolve (site2Dot);\r
 337                 }\r
 338 \r
 339                 void SubTestResolve (string addr)\r
 340                 {\r
 341                         IPHostEntry h = Dns.Resolve (addr);\r
 342                         SubTestValidIPHostEntry (h);\r
 343                 }\r
 344 \r
 345                 [Test]\r
 346                 public void Resolve_HostName_Null ()\r
 347                 {\r
 348                         try {\r
 349                                 Dns.Resolve ((string) null);\r
 350                                 Assert.Fail ("#1");\r
 351                         } catch (ArgumentNullException ex) {\r
 352                                 Assert.AreEqual (typeof (ArgumentNullException), ex.GetType (), "#2");\r
 353                                 Assert.IsNull (ex.InnerException, "#3");\r
 354                                 Assert.IsNotNull (ex.Message, "#4");\r
 355                                 Assert.AreEqual ("hostName", ex.ParamName, "#5");\r
 356                         }\r
 357                 }\r
 358 \r
 359                 [Test] // BeginGetHostEntry (IPAddress, AsyncCallback, Object)\r
 360                 public void BeginGetHostEntry1_Address_Null ()\r
 361                 {\r
 362                         try {\r
 363                                 Dns.BeginGetHostEntry (\r
 364                                         (IPAddress) null,\r
 365                                         new AsyncCallback (GetHostAddressesCallback),\r
 366                                         null);\r
 367                                 Assert.Fail ("#1");\r
 368                         } catch (ArgumentNullException ex) {\r
 369                                 Assert.AreEqual (typeof (ArgumentNullException), ex.GetType (), "#2");\r
 370                                 Assert.IsNull (ex.InnerException, "#3");\r
 371                                 Assert.IsNotNull (ex.Message, "#4");\r
 372                                 Assert.AreEqual ("address", ex.ParamName, "#5");\r
 373                         }\r
 374                 }\r
 375 \r
 376                 [Test] // BeginGetHostEntry (String, AsyncCallback, Object)\r
 377                 public void BeginGetHostEntry2_HostNameOrAddress_Null ()\r
 378                 {\r
 379                         try {\r
 380                                 Dns.BeginGetHostEntry (\r
 381                                         (string) null,\r
 382                                         new AsyncCallback (GetHostAddressesCallback),\r
 383                                         null);\r
 384                                 Assert.Fail ("#1");\r
 385                         } catch (ArgumentNullException ex) {\r
 386                                 Assert.AreEqual (typeof (ArgumentNullException), ex.GetType (), "#2");\r
 387                                 Assert.IsNull (ex.InnerException, "#3");\r
 388                                 Assert.IsNotNull (ex.Message, "#4");\r
 389                                 Assert.AreEqual ("hostName", ex.ParamName, "#5");\r
 390                         }\r
 391                 }\r
 392 \r
 393                 [Test] // BeginGetHostEntry (String, AsyncCallback, Object)\r
 394                 public void BeginGetHostEntry2_HostNameOrAddress_UnspecifiedAddress ()\r
 395                 {\r
 396                         // IPv4\r
 397                         try {\r
 398                                 Dns.BeginGetHostEntry (\r
 399                                         "0.0.0.0",\r
 400                                         new AsyncCallback (GetHostEntryCallback),\r
 401                                         null);\r
 402                                 Assert.Fail ("#1");\r
 403                         } catch (ArgumentException ex) {\r
 404                                 // IPv4 address 0.0.0.0 and IPv6 address ::0 are\r
 405                                 // unspecified addresses that cannot be used as\r
 406                                 // a target address\r
 407                                 Assert.AreEqual (typeof (ArgumentException), ex.GetType (), "#2");\r
 408                                 Assert.IsNull (ex.InnerException, "#3");\r
 409                                 Assert.IsNotNull (ex.Message, "#4");\r
 410                                 Assert.AreEqual ("hostNameOrAddress", ex.ParamName, "#5");\r
 411                         }\r
 412 \r
 413                         // IPv6\r
 414                         try {\r
 415                                 Dns.BeginGetHostEntry (\r
 416                                         "::0",\r
 417                                         new AsyncCallback (GetHostEntryCallback),\r
 418                                         null);\r
 419                                 Assert.Fail ("#1");\r
 420                         } catch (ArgumentException ex) {\r
 421                                 // IPv4 address 0.0.0.0 and IPv6 address ::0 are\r
 422                                 // unspecified addresses that cannot be used as\r
 423                                 // a target address\r
 424                                 Assert.AreEqual (typeof (ArgumentException), ex.GetType (), "#2");\r
 425                                 Assert.IsNull (ex.InnerException, "#3");\r
 426                                 Assert.IsNotNull (ex.Message, "#4");\r
 427                                 Assert.AreEqual ("hostNameOrAddress", ex.ParamName, "#5");\r
 428                         }\r
 429                 }\r
 430 \r
 431                 void GetHostEntryCallback (IAsyncResult ar)\r
 432                 {\r
 433                         IPHostEntry hostEntry = Dns.EndGetHostEntry (ar);\r
 434                         Assert.IsNotNull (hostEntry);\r
 435                 }\r
 436 \r
 437                 [Test] // GetHostEntry (IPAddress)\r
 438                 public void GetHostEntry1_Address_Null ()\r
 439                 {\r
 440                         try {\r
 441                                 Dns.GetHostEntry ((IPAddress) null);\r
 442                                 Assert.Fail ("#1");\r
 443                         } catch (ArgumentNullException ex) {\r
 444                                 Assert.AreEqual (typeof (ArgumentNullException), ex.GetType (), "#2");\r
 445                                 Assert.IsNull (ex.InnerException, "#3");\r
 446                                 Assert.IsNotNull (ex.Message, "#4");\r
 447                                 Assert.AreEqual ("address", ex.ParamName, "#5");\r
 448                         }\r
 449                 }\r
 450 \r
 451                 [Test] // GetHostEntry (String)\r
 452                 public void GetHostEntry2 ()\r
 453                 {\r
 454                         Dns.GetHostEntry (site1Name); // hostname\r
 455                         Dns.GetHostEntry (site1Dot); // IP address\r
 456                 }\r
 457 \r
 458                 [Test] // GetHostEntry (String)\r
 459                 public void GetHostEntry2_HostNameOrAddress_Null ()\r
 460                 {\r
 461                         try {\r
 462                                 Dns.GetHostEntry ((string) null);\r
 463                                 Assert.Fail ("#1");\r
 464                         } catch (ArgumentNullException ex) {\r
 465                                 Assert.AreEqual (typeof (ArgumentNullException), ex.GetType (), "#2");\r
 466                                 Assert.IsNull (ex.InnerException, "#3");\r
 467                                 Assert.IsNotNull (ex.Message, "#4");\r
 468                                 Assert.AreEqual ("hostNameOrAddress", ex.ParamName, "#5");\r
 469                         }\r
 470                 }\r
 471 \r
 472                 [Test] // GetHostEntry (String)\r
 473                 public void GetHostEntry2_HostNameOrAddress_UnspecifiedAddress ()\r
 474                 {\r
 475                         // IPv4\r
 476                         try {\r
 477                                 Dns.GetHostEntry ("0.0.0.0");\r
 478                                 Assert.Fail ("#A1");\r
 479                         } catch (ArgumentException ex) {\r
 480                                 // IPv4 address 0.0.0.0 and IPv6 address ::0 are\r
 481                                 // unspecified addresses that cannot be used as\r
 482                                 // a target address\r
 483                                 Assert.AreEqual (typeof (ArgumentException), ex.GetType (), "#A2");\r
 484                                 Assert.IsNull (ex.InnerException, "#A3");\r
 485                                 Assert.IsNotNull (ex.Message, "#A4");\r
 486                                 Assert.AreEqual ("hostNameOrAddress", ex.ParamName, "#A5");\r
 487                         }\r
 488 \r
 489                         // IPv6\r
 490                         try {\r
 491                                 Dns.GetHostEntry ("::0");\r
 492                                 Assert.Fail ("#B1");\r
 493                         } catch (ArgumentException ex) {\r
 494                                 // IPv4 address 0.0.0.0 and IPv6 address ::0 are\r
 495                                 // unspecified addresses that cannot be used as\r
 496                                 // a target address\r
 497                                 Assert.AreEqual (typeof (ArgumentException), ex.GetType (), "#B2");\r
 498                                 Assert.IsNull (ex.InnerException, "#B3");\r
 499                                 Assert.IsNotNull (ex.Message, "#B4");\r
 500                                 Assert.AreEqual ("hostNameOrAddress", ex.ParamName, "#B5");\r
 501                         }\r
 502                 }\r
 503 \r
 504                 void SubTestValidIPHostEntry (IPHostEntry h)\r
 505                 {\r
 506                         Assert.IsNotNull (h.HostName, "HostName not null");\r
 507                         Assert.IsNotNull (h.AddressList, "AddressList not null");\r
 508                         Assert.IsTrue (h.AddressList.Length > 0, "AddressList.Length");\r
 509                 }\r
 510 \r
 511                 [Test]\r
 512                 public void GetHostEntry_StringEmpty ()\r
 513                 {\r
 514                         Dns.GetHostEntry (string.Empty);\r
 515                 }\r
 516 \r
 517                 /* This isn't used anymore, but could be useful for debugging\r
 518                 static void printIPHostEntry(IPHostEntry h)\r
 519                 {\r
 520                         Console.WriteLine("----------------------------------------------------");\r
 521                         Console.WriteLine("Host name:");\r
 522                         Console.WriteLine(h.HostName);\r
 523                         Console.WriteLine("IP addresses:");\r
 524                         IPAddress[] list = h.AddressList;\r
 525                         for(int i = 0; i < list.Length; ++i)\r
 526                                 Console.WriteLine(list[i]);\r
 527                         Console.WriteLine("Aliases:");\r
 528                         string[] aliases = h.Aliases;\r
 529                         for(int i = 0; i < aliases.Length; ++i)\r
 530                                 Console.WriteLine(aliases[i]);\r
 531                         Console.WriteLine("----------------------------------------------------");\r
 532                 }\r
 533                 */\r
 534         }\r
 535 }\r