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 \r
  11 using System;\r
  12 using System.Linq;\r
  13 using System.Net;\r
  14 using System.Net.Sockets;\r
  15 using System.Threading;\r
  16 \r
  17 using NUnit.Framework;\r
  18 \r
  19 namespace MonoTests.System.Net\r
  20 {\r
  21         [TestFixture]\r
  22         [Category ("RequiresBSDSockets")]\r
  23         public class DnsTest\r
  24         {\r
  25                 private String site1Name = "google-public-dns-a.google.com",\r
  26                         site1Dot = "8.8.8.8",\r
  27                         site2Name = "google-public-dns-b.google.com",\r
  28                         site2Dot = "8.8.4.4",\r
  29                         noneExistingSite = "unlikely.xamarin.com";\r
  30                 private uint site1IP = 134744072, site2IP = 134743044; // Big-Endian\r
  31 \r
  32                 [Test]\r
  33                 public void AsyncGetHostByName ()\r
  34                 {\r
  35                         IAsyncResult r;\r
  36                         r = Dns.BeginGetHostByName (site1Name, new AsyncCallback (GetHostByNameCallback), null);\r
  37 \r
  38                         IAsyncResult async = Dns.BeginGetHostByName (site1Name, null, null);\r
  39                         IPHostEntry entry = Dns.EndGetHostByName (async);\r
  40                         SubTestValidIPHostEntry (entry);\r
  41                         Assert.IsTrue (entry.HostName == "google-public-dns-a.google.com");\r
  42                 }\r
  43 \r
  44                 void GetHostByNameCallback (IAsyncResult ar)\r
  45                 {\r
  46                         IPHostEntry h;\r
  47                         h = Dns.EndGetHostByName (ar);\r
  48                         SubTestValidIPHostEntry (h);\r
  49                 }\r
  50 \r
  51                 [Test]\r
  52                 public void AsyncResolve ()\r
  53                 {\r
  54                         IAsyncResult r;\r
  55                         r = Dns.BeginResolve (site1Name, new AsyncCallback (ResolveCallback), null);\r
  56 \r
  57                         IAsyncResult async = Dns.BeginResolve (site1Dot, null, null);\r
  58                         IPHostEntry entry = Dns.EndResolve (async);\r
  59                         SubTestValidIPHostEntry (entry);\r
  60                         var ip = GetIPv4Address (entry);\r
  61                         Assert.AreEqual (site1Dot, ip.ToString ());\r
  62                 }\r
  63 \r
  64                 void ResolveCallback (IAsyncResult ar)\r
  65                 {\r
  66                         IPHostEntry h = Dns.EndResolve (ar);\r
  67                         SubTestValidIPHostEntry (h);\r
  68                 }\r
  69 \r
  70                 [Test]\r
  71                 public void BeginGetHostAddresses_HostNameOrAddress_Null ()\r
  72                 {\r
  73                         try {\r
  74                                 Dns.BeginGetHostAddresses (\r
  75                                         (string) null,\r
  76                                         new AsyncCallback (GetHostAddressesCallback),\r
  77                                         null);\r
  78                                 Assert.Fail ("#1");\r
  79                         } catch (ArgumentNullException ex) {\r
  80                                 Assert.AreEqual (typeof (ArgumentNullException), ex.GetType (), "#2");\r
  81                                 Assert.IsNull (ex.InnerException, "#3");\r
  82                                 Assert.IsNotNull (ex.Message, "#4");\r
  83                                 Assert.AreEqual ("hostName", ex.ParamName, "#5");\r
  84                         }\r
  85                 }\r
  86 \r
  87                 [Test]\r
  88                 public void BeginGetHostAddresses_HostNameOrAddress_UnspecifiedAddress ()\r
  89                 {\r
  90                         // IPv4\r
  91                         try {\r
  92                                 Dns.BeginGetHostAddresses (\r
  93                                         "0.0.0.0",\r
  94                                         new AsyncCallback (GetHostAddressesCallback),\r
  95                                         null);\r
  96                                 Assert.Fail ("#A1");\r
  97                         } catch (ArgumentException ex) {\r
  98                                 // IPv4 address 0.0.0.0 and IPv6 address ::0 are\r
  99                                 // unspecified addresses that cannot be used as\r
 100                                 // a target address\r
 101                                 Assert.AreEqual (typeof (ArgumentException), ex.GetType (), "#A2");\r
 102                                 Assert.IsNull (ex.InnerException, "#A3");\r
 103                                 Assert.IsNotNull (ex.Message, "#A4");\r
 104                                 Assert.AreEqual ("hostNameOrAddress", ex.ParamName, "#A5");\r
 105                         }\r
 106 \r
 107                         // IPv6\r
 108                         try {\r
 109                                 Dns.BeginGetHostAddresses (\r
 110                                         "::0",\r
 111                                         new AsyncCallback (GetHostAddressesCallback),\r
 112                                         null);\r
 113                                 Assert.Fail ("#B1");\r
 114                         } catch (ArgumentException ex) {\r
 115                                 // IPv4 address 0.0.0.0 and IPv6 address ::0 are\r
 116                                 // unspecified addresses that cannot be used as\r
 117                                 // a target address\r
 118                                 Assert.AreEqual (typeof (ArgumentException), ex.GetType (), "#B2");\r
 119                                 Assert.IsNull (ex.InnerException, "#B3");\r
 120                                 Assert.IsNotNull (ex.Message, "#B4");\r
 121                                 Assert.AreEqual ("hostNameOrAddress", ex.ParamName, "#B5");\r
 122                         }\r
 123                 }\r
 124 \r
 125                 void GetHostAddressesCallback (IAsyncResult ar)\r
 126                 {\r
 127                         IPAddress [] addresses = Dns.EndGetHostAddresses (ar);\r
 128                         Assert.IsNotNull (addresses);\r
 129                 }\r
 130 \r
 131                 [Test]\r
 132                 public void GetHostAddresses_HostNameOrAddress_Null ()\r
 133                 {\r
 134                         try {\r
 135                                 Dns.GetHostAddresses ((string) null);\r
 136                                 Assert.Fail ("#1");\r
 137                         } catch (ArgumentNullException ex) {\r
 138                                 Assert.AreEqual (typeof (ArgumentNullException), ex.GetType (), "#2");\r
 139                                 Assert.IsNull (ex.InnerException, "#3");\r
 140                                 Assert.IsNotNull (ex.Message, "#4");\r
 141                                 Assert.AreEqual ("hostNameOrAddress", ex.ParamName, "#5");\r
 142                         }\r
 143                 }\r
 144 \r
 145                 [Test]\r
 146                 public void GetHostAddresses_HostNameOrAddress_UnspecifiedAddress ()\r
 147                 {\r
 148                         // IPv4\r
 149                         try {\r
 150                                 Dns.GetHostAddresses ("0.0.0.0");\r
 151                                 Assert.Fail ("#A1");\r
 152                         } catch (ArgumentException ex) {\r
 153                                 // IPv4 address 0.0.0.0 and IPv6 address ::0 are\r
 154                                 // unspecified addresses that cannot be used as\r
 155                                 // a target address\r
 156                                 Assert.AreEqual (typeof (ArgumentException), ex.GetType (), "#A2");\r
 157                                 Assert.IsNull (ex.InnerException, "#A3");\r
 158                                 Assert.IsNotNull (ex.Message, "#A4");\r
 159                                 Assert.AreEqual ("hostNameOrAddress", ex.ParamName, "#A5");\r
 160                         }\r
 161 \r
 162                         // IPv6\r
 163                         try {\r
 164                                 Dns.GetHostAddresses ("::0");\r
 165                                 Assert.Fail ("#B1");\r
 166                         } catch (ArgumentException ex) {\r
 167                                 // IPv4 address 0.0.0.0 and IPv6 address ::0 are\r
 168                                 // unspecified addresses that cannot be used as\r
 169                                 // a target address\r
 170                                 Assert.AreEqual (typeof (ArgumentException), ex.GetType (), "#B2");\r
 171                                 Assert.IsNull (ex.InnerException, "#B3");\r
 172                                 Assert.IsNotNull (ex.Message, "#B4");\r
 173                                 Assert.AreEqual ("hostNameOrAddress", ex.ParamName, "#B5");\r
 174                         }\r
 175                 }\r
 176 \r
 177                 [Test]\r
 178                 public void GetHostName ()\r
 179                 {\r
 180                         string hostName = Dns.GetHostName ();\r
 181                         Assert.IsNotNull (hostName);\r
 182                 }\r
 183 \r
 184                 [Test]\r
 185                 public void GetHostByName ()\r
 186                 {\r
 187                         SubTestGetHostByName (site1Name, site1Dot);\r
 188                         SubTestGetHostByName (site2Name, site2Dot);\r
 189                         try {\r
 190                                 var entry = Dns.GetHostByName (noneExistingSite);\r
 191                                 /*\r
 192                                  * Work around broken t-online.de DNS Server.\r
 193                                  * \r
 194                                  * T-Online's DNS Server for DSL Customers resolves\r
 195                                  * non-exisitng domain names to\r
 196                                  * http://navigationshilfe1.t-online.de/dnserror?url=....\r
 197                                  * instead of reporting an error.\r
 198                                  */\r
 199                                 var navigationshilfe1 = IPAddress.Parse ("80.156.86.78");\r
 200                                 var navigationshilfe2 = IPAddress.Parse ("62.157.140.133");\r
 201                                 foreach (var addr in entry.AddressList) {\r
 202                                         if (addr.Equals (navigationshilfe1) || addr.Equals (navigationshilfe2))\r
 203                                                 return;\r
 204                                 }\r
 205                                 Assert.Fail ("Should raise a SocketException (assuming that '" + noneExistingSite + "' does not exist)");\r
 206                         } catch (SocketException) {\r
 207                         }\r
 208                 }\r
 209 \r
 210                 static IPAddress GetIPv4Address (IPHostEntry h)\r
 211                 {\r
 212                         var al = h.AddressList.FirstOrDefault (x => x.AddressFamily == AddressFamily.InterNetwork);\r
 213                         if (al == null)\r
 214                                 Assert.Ignore ("Could not resolve an IPv4 address as required by this test case, e.g. running on an IPv6 only network");\r
 215                         return al;\r
 216                 }\r
 217 \r
 218                 void SubTestGetHostByName (string siteName, string siteDot)\r
 219                 {\r
 220                         IPHostEntry h = Dns.GetHostByName (siteName);\r
 221                         SubTestValidIPHostEntry (h);\r
 222                         Assert.AreEqual (siteName, h.HostName, "siteName");\r
 223                         var ip = GetIPv4Address (h);\r
 224                         Assert.AreEqual (siteDot, ip.ToString (), "siteDot");\r
 225                 }\r
 226 \r
 227                 [Test]\r
 228                 public void GetHostByName_HostName_Null ()\r
 229                 {\r
 230                         try {\r
 231                                 Dns.GetHostByName ((string) null);\r
 232                                 Assert.Fail ("#1");\r
 233                         } catch (ArgumentNullException ex) {\r
 234                                 Assert.AreEqual (typeof (ArgumentNullException), ex.GetType (), "#2");\r
 235                                 Assert.IsNull (ex.InnerException, "#3");\r
 236                                 Assert.IsNotNull (ex.Message, "#4");\r
 237                                 Assert.AreEqual ("hostName", ex.ParamName, "#5");\r
 238                         }\r
 239                 }\r
 240 \r
 241                 [Test]\r
 242                 public void GetHostByAddressString_Address_Null ()\r
 243                 {\r
 244                         try {\r
 245                                 Dns.GetHostByAddress ((string) null);\r
 246                                 Assert.Fail ("#1");\r
 247                         } catch (ArgumentNullException ex) {\r
 248                                 Assert.AreEqual (typeof (ArgumentNullException), ex.GetType (), "#2");\r
 249                                 Assert.IsNull (ex.InnerException, "#3");\r
 250                                 Assert.IsNotNull (ex.Message, "#4");\r
 251                                 Assert.AreEqual ("address", ex.ParamName, "#5");\r
 252                         }\r
 253                 }\r
 254 \r
 255                 [Test]\r
 256                 [ExpectedException (typeof (SocketException))]\r
 257                 public void GetHostByAddressString2 ()\r
 258                 {\r
 259                         Dns.GetHostByAddress ("123.255.23");\r
 260                 }\r
 261 \r
 262                 [Test]\r
 263                 [ExpectedException (typeof (FormatException))]\r
 264                 public void GetHostByAddressString3 ()\r
 265                 {\r
 266                         Dns.GetHostByAddress ("123.256.34.10");\r
 267                 }\r
 268 \r
 269                 [Test, ExpectedException (typeof (FormatException))]\r
 270                 public void GetHostByAddressString4 ()\r
 271                 {\r
 272                         Dns.GetHostByAddress ("not an IP address");\r
 273                 }\r
 274 \r
 275                 [Test]\r
 276                 public void GetHostByAddressString5 ()\r
 277                 {\r
 278                         Dns.GetHostByAddress (site1Dot);\r
 279                 }\r
 280 \r
 281                 [Test]\r
 282                 public void GetHostByAddressIPAddress_Address_Null ()\r
 283                 {\r
 284                         try {\r
 285                                 Dns.GetHostByAddress ((IPAddress) null);\r
 286                                 Assert.Fail ("#1");\r
 287                         } catch (ArgumentNullException ex) {\r
 288                                 Assert.AreEqual (typeof (ArgumentNullException), ex.GetType (), "#2");\r
 289                                 Assert.IsNull (ex.InnerException, "#3");\r
 290                                 Assert.IsNotNull (ex.Message, "#4");\r
 291                                 Assert.AreEqual ("address", ex.ParamName, "#5");\r
 292                         }\r
 293                 }\r
 294 \r
 295                 [Test]\r
 296                 public void GetHostByAddressIPAddress2 ()\r
 297                 {\r
 298                         IPAddress addr = new IPAddress (IPAddress.NetworkToHostOrder ((int) site1IP));\r
 299                         IPHostEntry h = Dns.GetHostByAddress (addr);\r
 300                         SubTestValidIPHostEntry (h);\r
 301                         var ip = GetIPv4Address (h);\r
 302                         Assert.AreEqual (addr.ToString (), ip.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                         var ip = GetIPv4Address (h);\r
 312                         Assert.AreEqual (addr.ToString (), ip.ToString ());\r
 313                 }\r
 314 \r
 315                 [Test]\r
 316                 public void BeginResolve_HostName_Null ()\r
 317                 {\r
 318                         try {\r
 319                                 Dns.BeginResolve ((string) null,\r
 320                                         new AsyncCallback (ResolveCallback),\r
 321                                         null);\r
 322                                 Assert.Fail ("#1");\r
 323                         } catch (ArgumentNullException ex) {\r
 324                                 Assert.AreEqual (typeof (ArgumentNullException), ex.GetType (), "#2");\r
 325                                 Assert.IsNull (ex.InnerException, "#3");\r
 326                                 Assert.IsNotNull (ex.Message, "#4");\r
 327                                 Assert.AreEqual ("hostName", ex.ParamName, "#5");\r
 328                         }\r
 329                 }\r
 330 \r
 331                 [Test]\r
 332                 public void Resolve ()\r
 333                 {\r
 334                         SubTestResolve (site1Name);\r
 335                         SubTestResolve (site2Name);\r
 336                         SubTestResolve (site1Dot);\r
 337                         SubTestResolve (site2Dot);\r
 338                 }\r
 339 \r
 340                 void SubTestResolve (string addr)\r
 341                 {\r
 342                         IPHostEntry h = Dns.Resolve (addr);\r
 343                         SubTestValidIPHostEntry (h);\r
 344                 }\r
 345 \r
 346                 [Test]\r
 347                 public void Resolve_HostName_Null ()\r
 348                 {\r
 349                         try {\r
 350                                 Dns.Resolve ((string) null);\r
 351                                 Assert.Fail ("#1");\r
 352                         } catch (ArgumentNullException ex) {\r
 353                                 Assert.AreEqual (typeof (ArgumentNullException), ex.GetType (), "#2");\r
 354                                 Assert.IsNull (ex.InnerException, "#3");\r
 355                                 Assert.IsNotNull (ex.Message, "#4");\r
 356                                 Assert.AreEqual ("hostName", ex.ParamName, "#5");\r
 357                         }\r
 358                 }\r
 359 \r
 360                 [Test] // BeginGetHostEntry (IPAddress, AsyncCallback, Object)\r
 361                 public void BeginGetHostEntry1_Address_Null ()\r
 362                 {\r
 363                         try {\r
 364                                 Dns.BeginGetHostEntry (\r
 365                                         (IPAddress) null,\r
 366                                         new AsyncCallback (GetHostAddressesCallback),\r
 367                                         null);\r
 368                                 Assert.Fail ("#1");\r
 369                         } catch (ArgumentNullException ex) {\r
 370                                 Assert.AreEqual (typeof (ArgumentNullException), ex.GetType (), "#2");\r
 371                                 Assert.IsNull (ex.InnerException, "#3");\r
 372                                 Assert.IsNotNull (ex.Message, "#4");\r
 373                                 Assert.AreEqual ("address", ex.ParamName, "#5");\r
 374                         }\r
 375                 }\r
 376 \r
 377                 [Test] // BeginGetHostEntry (String, AsyncCallback, Object)\r
 378                 public void BeginGetHostEntry2_HostNameOrAddress_Null ()\r
 379                 {\r
 380                         try {\r
 381                                 Dns.BeginGetHostEntry (\r
 382                                         (string) null,\r
 383                                         new AsyncCallback (GetHostAddressesCallback),\r
 384                                         null);\r
 385                                 Assert.Fail ("#1");\r
 386                         } catch (ArgumentNullException ex) {\r
 387                                 Assert.AreEqual (typeof (ArgumentNullException), ex.GetType (), "#2");\r
 388                                 Assert.IsNull (ex.InnerException, "#3");\r
 389                                 Assert.IsNotNull (ex.Message, "#4");\r
 390                                 Assert.AreEqual ("hostName", ex.ParamName, "#5");\r
 391                         }\r
 392                 }\r
 393 \r
 394                 [Test] // BeginGetHostEntry (String, AsyncCallback, Object)\r
 395                 public void BeginGetHostEntry2_HostNameOrAddress_UnspecifiedAddress ()\r
 396                 {\r
 397                         // IPv4\r
 398                         try {\r
 399                                 Dns.BeginGetHostEntry (\r
 400                                         "0.0.0.0",\r
 401                                         new AsyncCallback (GetHostEntryCallback),\r
 402                                         null);\r
 403                                 Assert.Fail ("#1");\r
 404                         } catch (ArgumentException ex) {\r
 405                                 // IPv4 address 0.0.0.0 and IPv6 address ::0 are\r
 406                                 // unspecified addresses that cannot be used as\r
 407                                 // a target address\r
 408                                 Assert.AreEqual (typeof (ArgumentException), ex.GetType (), "#2");\r
 409                                 Assert.IsNull (ex.InnerException, "#3");\r
 410                                 Assert.IsNotNull (ex.Message, "#4");\r
 411                                 Assert.AreEqual ("hostNameOrAddress", ex.ParamName, "#5");\r
 412                         }\r
 413 \r
 414                         // IPv6\r
 415                         try {\r
 416                                 Dns.BeginGetHostEntry (\r
 417                                         "::0",\r
 418                                         new AsyncCallback (GetHostEntryCallback),\r
 419                                         null);\r
 420                                 Assert.Fail ("#1");\r
 421                         } catch (ArgumentException ex) {\r
 422                                 // IPv4 address 0.0.0.0 and IPv6 address ::0 are\r
 423                                 // unspecified addresses that cannot be used as\r
 424                                 // a target address\r
 425                                 Assert.AreEqual (typeof (ArgumentException), ex.GetType (), "#2");\r
 426                                 Assert.IsNull (ex.InnerException, "#3");\r
 427                                 Assert.IsNotNull (ex.Message, "#4");\r
 428                                 Assert.AreEqual ("hostNameOrAddress", ex.ParamName, "#5");\r
 429                         }\r
 430                 }\r
 431 \r
 432                 void GetHostEntryCallback (IAsyncResult ar)\r
 433                 {\r
 434                         IPHostEntry hostEntry = Dns.EndGetHostEntry (ar);\r
 435                         Assert.IsNotNull (hostEntry);\r
 436                 }\r
 437 \r
 438                 [Test] // GetHostEntry (IPAddress)\r
 439                 public void GetHostEntry1_Address_Null ()\r
 440                 {\r
 441                         try {\r
 442                                 Dns.GetHostEntry ((IPAddress) null);\r
 443                                 Assert.Fail ("#1");\r
 444                         } catch (ArgumentNullException ex) {\r
 445                                 Assert.AreEqual (typeof (ArgumentNullException), ex.GetType (), "#2");\r
 446                                 Assert.IsNull (ex.InnerException, "#3");\r
 447                                 Assert.IsNotNull (ex.Message, "#4");\r
 448                                 Assert.AreEqual ("address", ex.ParamName, "#5");\r
 449                         }\r
 450                 }\r
 451 \r
 452                 [Test] // GetHostEntry (String)\r
 453                 public void GetHostEntry2 ()\r
 454                 {\r
 455                         Dns.GetHostEntry (site1Name); // hostname\r
 456                         Dns.GetHostEntry (site1Dot); // IP address\r
 457                 }\r
 458 \r
 459                 [Test] // GetHostEntry (String)\r
 460                 public void GetHostEntry2_HostNameOrAddress_Null ()\r
 461                 {\r
 462                         try {\r
 463                                 Dns.GetHostEntry ((string) null);\r
 464                                 Assert.Fail ("#1");\r
 465                         } catch (ArgumentNullException ex) {\r
 466                                 Assert.AreEqual (typeof (ArgumentNullException), ex.GetType (), "#2");\r
 467                                 Assert.IsNull (ex.InnerException, "#3");\r
 468                                 Assert.IsNotNull (ex.Message, "#4");\r
 469                                 Assert.AreEqual ("hostNameOrAddress", ex.ParamName, "#5");\r
 470                         }\r
 471                 }\r
 472 \r
 473                 [Test] // GetHostEntry (String)\r
 474                 public void GetHostEntry2_HostNameOrAddress_UnspecifiedAddress ()\r
 475                 {\r
 476                         // IPv4\r
 477                         try {\r
 478                                 Dns.GetHostEntry ("0.0.0.0");\r
 479                                 Assert.Fail ("#A1");\r
 480                         } catch (ArgumentException ex) {\r
 481                                 // IPv4 address 0.0.0.0 and IPv6 address ::0 are\r
 482                                 // unspecified addresses that cannot be used as\r
 483                                 // a target address\r
 484                                 Assert.AreEqual (typeof (ArgumentException), ex.GetType (), "#A2");\r
 485                                 Assert.IsNull (ex.InnerException, "#A3");\r
 486                                 Assert.IsNotNull (ex.Message, "#A4");\r
 487                                 Assert.AreEqual ("hostNameOrAddress", ex.ParamName, "#A5");\r
 488                         }\r
 489 \r
 490                         // IPv6\r
 491                         try {\r
 492                                 Dns.GetHostEntry ("::0");\r
 493                                 Assert.Fail ("#B1");\r
 494                         } catch (ArgumentException ex) {\r
 495                                 // IPv4 address 0.0.0.0 and IPv6 address ::0 are\r
 496                                 // unspecified addresses that cannot be used as\r
 497                                 // a target address\r
 498                                 Assert.AreEqual (typeof (ArgumentException), ex.GetType (), "#B2");\r
 499                                 Assert.IsNull (ex.InnerException, "#B3");\r
 500                                 Assert.IsNotNull (ex.Message, "#B4");\r
 501                                 Assert.AreEqual ("hostNameOrAddress", ex.ParamName, "#B5");\r
 502                         }\r
 503                 }\r
 504 \r
 505                 void SubTestValidIPHostEntry (IPHostEntry h)\r
 506                 {\r
 507                         Assert.IsNotNull (h.HostName, "HostName not null");\r
 508                         Assert.IsNotNull (h.AddressList, "AddressList not null");\r
 509                         Assert.IsTrue (h.AddressList.Length > 0, "AddressList.Length");\r
 510                 }\r
 511 \r
 512                 [Test]\r
 513                 public void GetHostEntry_StringEmpty ()\r
 514                 {\r
 515                         Dns.GetHostEntry (string.Empty);\r
 516                 }\r
 517 \r
 518                 /* This isn't used anymore, but could be useful for debugging\r
 519                 static void printIPHostEntry(IPHostEntry h)\r
 520                 {\r
 521                         Console.WriteLine("----------------------------------------------------");\r
 522                         Console.WriteLine("Host name:");\r
 523                         Console.WriteLine(h.HostName);\r
 524                         Console.WriteLine("IP addresses:");\r
 525                         IPAddress[] list = h.AddressList;\r
 526                         for(int i = 0; i < list.Length; ++i)\r
 527                                 Console.WriteLine(list[i]);\r
 528                         Console.WriteLine("Aliases:");\r
 529                         string[] aliases = h.Aliases;\r
 530                         for(int i = 0; i < aliases.Length; ++i)\r
 531                                 Console.WriteLine(aliases[i]);\r
 532                         Console.WriteLine("----------------------------------------------------");\r
 533                 }\r
 534                 */\r
 535         }\r
 536 }\r