Feature/sql exception bug check (#90)

* Added test for OSX/Linux to check for the SqlException error code bug in .NET core

* fix style

* closed summary

test/Microsoft.SqlTools.ServiceLayer.Test/Connection/ConnectionServiceTests.cs

@@ -7,6 +7,7 @@ using System;
 using System.Collections.Generic;
 using System.Data;
 using System.Data.Common;
+using System.Data.SqlClient;
 using System.Reflection;
 using System.Threading;
 using System.Threading.Tasks;
@@ -830,5 +831,35 @@ namespace Microsoft.SqlTools.ServiceLayer.Test.Connection
             ConnectionInfo info;
             Assert.True(service.TryFindConnection(connectParams.OwnerUri, out info));
         }
+
+        /// <summary>
+        /// Verify that Linux/OSX SqlExceptions thrown do not contain an error code.
+        /// This is a bug in .NET core (see https://github.com/dotnet/corefx/issues/12472).
+        /// If this test ever fails, it means that this bug has been fixed. When this is
+        /// the case, look at RetryPolicyUtils.cs in IsRetryableNetworkConnectivityError(),
+        /// and remove the code block specific to Linux/OSX.
+        /// </summary>
+        [Fact]
+        public void TestThatLinuxAndOSXSqlExceptionHasNoErrorCode()
+        {
+            TestUtils.RunIfLinuxOrOSX(() => 
+            {    
+                try
+                {
+                    SqlConnectionStringBuilder builder = new SqlConnectionStringBuilder();
+                    builder.DataSource = "bad-server-name";
+                    builder.UserID = "sa";
+                    builder.Password = "bad password";
+
+                    SqlConnection connection = new SqlConnection(builder.ConnectionString);
+                    connection.Open(); // This should fail
+                }
+                catch (SqlException ex)
+                {
+                    // Error code should be 0 due to bug
+                    Assert.Equal(ex.Number, 0);
+                }
+            });
+        }
     }
 }

test/Microsoft.SqlTools.ServiceLayer.Test/Utility/TestUtils.cs

@@ -14,6 +14,14 @@ namespace Microsoft.SqlTools.ServiceLayer.Test.Utility
                 test();
             }
         }
+
+        public static void RunIfLinuxOrOSX(Action test)
+        {
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux) || RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+            {
+                test();
+            }
+        }
         
         public static void RunIfWindows(Action test)
         {