commit

src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/SqlConnection.cs

@@ -1417,6 +1417,7 @@ private async Task ReconnectAsync(int timeout)
                             if (e.Class >= TdsEnums.FATAL_ERROR_CLASS)
                             {
                                 SqlClientEventSource.Log.TryTraceEvent("<sc.SqlConnection.ReconnectAsync|INFO> Original ClientConnectionID {0} - Fatal Error occured. Error Class: {1}", _originalConnectionId, e.Class);
+                                // Errors 20-25, usuallyterminate the database connection
                                 InnerConnection.CloseConnection(InnerConnection.Owner, ConnectionFactory);
                             }
                             throw SQL.CR_AllAttemptsFailed(e, _originalConnectionId);

src/Microsoft.Data.SqlClient/tests/ManualTests/SQL/ExceptionTest/ConnectionExceptionTest.cs

@@ -23,23 +23,30 @@ public void TestConnectionStateWithErrorClass20()
         {
             using TestTdsServer server = TestTdsServer.StartTestServer();
             using SqlConnection conn = new(server.ConnectionString);
+
             conn.Open();
             SqlCommand cmd = conn.CreateCommand();
             cmd.CommandText = "SELECT 1";
             int result = cmd.ExecuteNonQuery();
+
             Assert.Equal(-1, result);
-            Assert.Equal("Open", conn.State.ToString());
+            Assert.Equal(System.Data.ConnectionState.Open, conn.State);
+
             server.Dispose();
             try
             {
                 int result2 = cmd.ExecuteNonQuery();
             }
             catch (SqlException ex)
             {
-                Assert.True(ex.Class >= 20);
+                Assert.Equal(11, ex.Class);
+                Assert.NotNull(ex.InnerException);
+                SqlException innerEx = Assert.IsType<SqlException>(ex.InnerException);
+                Assert.Equal(20, innerEx.Class);
+                Assert.StartsWith("A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible.", innerEx.Message);
                 // Since the server is not accessible driver can close the close the connection
                 // It is user responsibilty to maintain the connection.
-                Assert.Equal("Closed", conn.State.ToString());
+                Assert.Equal(System.Data.ConnectionState.Closed, conn.State);
             }
         }