[dotnet] Align webdriver errors with spec

dotnet/src/webdriver/Remote/HttpCommandExecutor.cs

@@ -326,7 +326,7 @@ private Response CreateResponse(HttpResponseInfo responseInfo)
                 }
                 else
                 {
-                    response.Status = WebDriverResult.UnhandledError;
+                    response.Status = WebDriverResult.UnknownError;
                     response.Value = body;
                 }
             }

dotnet/src/webdriver/UnknownErrorException.cs

@@ -0,0 +1,51 @@
+// <copyright file="UnknownErrorException.cs" company="Selenium Committers">
+// Licensed to the Software Freedom Conservancy (SFC) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The SFC licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+// </copyright>
+
+using System;
+
+#nullable enable
+
+namespace OpenQA.Selenium
+{
+    /// <summary>
+    /// An unknown error occurred in the remote end while processing the command.
+    /// </summary>
+    [Serializable]
+    public class UnknownErrorException : WebDriverException
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="UnknownErrorException"/> class with the specified message.
+        /// </summary>
+        /// <param name="message">The message of the exception.</param>
+        public UnknownErrorException(string? message)
+            : base(message)
+        {
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="UnknownErrorException"/> class with the specified message and inner exception.
+        /// </summary>
+        /// <param name="message">The message of the exception.</param>
+        /// <param name="innerException">The inner exception for this exception.</param>
+        public UnknownErrorException(string? message, Exception? innerException)
+            : base(message, innerException)
+        {
+        }
+    }
+}

dotnet/src/webdriver/UnsupportedOperationException.cs

@@ -0,0 +1,50 @@
+// <copyright file="UnsupportedOperationException.cs" company="Selenium Committers">
+// Licensed to the Software Freedom Conservancy (SFC) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The SFC licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+// </copyright>
+
+using System;
+
+#nullable enable
+
+namespace OpenQA.Selenium
+{
+    /// <summary>
+    /// Indicates that a command that should have executed properly cannot be supported for some reason.
+    /// </summary>
+    public class UnsupportedOperationException : WebDriverException
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="UnsupportedOperationException"/> class with the specified message.
+        /// </summary>
+        /// <param name="message">The message of the exception.</param>
+        public UnsupportedOperationException(string? message)
+            : base(message)
+        {
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="UnsupportedOperationException"/> class with the specified message and inner exception.
+        /// </summary>
+        /// <param name="message">The message of the exception.</param>
+        /// <param name="innerException">The inner exception for this exception.</param>
+        public UnsupportedOperationException(string? message, Exception? innerException)
+            : base(message, innerException)
+        {
+        }
+    }
+}

dotnet/src/webdriver/WebDriver.cs

@@ -622,7 +622,7 @@ protected virtual async Task<Response> ExecuteAsync(string driverCommandToExecut
             {
                 commandResponse = new Response
                 {
-                    Status = WebDriverResult.UnhandledError,
+                    Status = WebDriverResult.UnknownError,
                     Value = e
                 };
             }
@@ -782,9 +782,6 @@ private static void UnpackAndThrowOnError(Response errorResponse, string command
                         case WebDriverResult.ElementNotSelectable:
                             throw new InvalidElementStateException(errorMessage);
 
-                        case WebDriverResult.UnhandledError:
-                            throw new WebDriverException(errorMessage);
-
                         case WebDriverResult.NoSuchDocument:
                             throw new NoSuchElementException(errorMessage);
 
@@ -854,6 +851,12 @@ private static void UnpackAndThrowOnError(Response errorResponse, string command
                         case WebDriverResult.InsecureCertificate:
                             throw new InsecureCertificateException(errorMessage);
 
+                        case WebDriverResult.UnknownError:
+                            throw new UnknownErrorException(errorMessage);
+
+                        case WebDriverResult.UnsupportedOperation:
+                            throw new UnsupportedOperationException(errorMessage);
+
                         default:
                             throw new InvalidOperationException(string.Format(CultureInfo.InvariantCulture, "{0} ({1})", errorMessage, errorResponse.Status));
                     }

dotnet/src/webdriver/WebDriverError.cs

@@ -223,9 +223,9 @@ static WebDriverError()
             resultMap[UnableToCaptureScreen] = WebDriverResult.UnableToCaptureScreen;
             resultMap[UnexpectedAlertOpen] = WebDriverResult.UnexpectedAlertOpen;
             resultMap[UnknownCommand] = WebDriverResult.UnknownCommand;
-            resultMap[UnknownError] = WebDriverResult.UnhandledError;
+            resultMap[UnknownError] = WebDriverResult.UnknownError;
             resultMap[UnknownMethod] = WebDriverResult.UnknownCommand;
-            resultMap[UnsupportedOperation] = WebDriverResult.UnhandledError;
+            resultMap[UnsupportedOperation] = WebDriverResult.UnsupportedOperation;
         }
 
         /// <summary>

dotnet/src/webdriver/WebDriverResult.cs

@@ -90,9 +90,9 @@ public enum WebDriverResult
         InvalidElementState = 12,
 
         /// <summary>
-        /// An unhandled error occurred.
+        /// An unknown error occurred in the remote end while processing the command.
         /// </summary>
-        UnhandledError = 13,
+        UnknownError = 13,
 
         /// <summary>
         /// An error occurred, but it was expected.
@@ -233,5 +233,10 @@ public enum WebDriverResult
         /// The referenced shadow root is no longer attached to the DOM.
         /// </summary>
         DetachedShadowRoot = 66,
+
+        /// <summary>
+        /// Indicates that a command that should have executed properly cannot be supported for some reason.
+        /// </summary>
+        UnsupportedOperation = 67,
     }
 }