Avoid exceptions in command-specific telemetry events (#421)

Author: tlmii

src/Microsoft.HttpRepl/Telemetry/Events/PreferenceEvent.cs

@@ -17,7 +17,8 @@ public PreferenceEvent(string getOrSet, string preferenceName) : base(TelemetryE
 
         private static string SanitizePreferenceName(string preferenceName)
         {
-            if (WellKnownPreference.Catalog.Names.Contains(preferenceName, StringComparer.OrdinalIgnoreCase))
+            if (string.IsNullOrEmpty(preferenceName) ||
+                WellKnownPreference.Catalog.Names.Contains(preferenceName, StringComparer.OrdinalIgnoreCase))
             {
                 return preferenceName;
             }

src/Microsoft.HttpRepl/Telemetry/Events/SetHeaderEvent.cs

@@ -16,7 +16,8 @@ public SetHeaderEvent(string headerName, bool isValueEmpty) : base(TelemetryEven
 
         private static string SanitizeHeaderName(string headerName)
         {
-            if (WellKnownHeaders.CommonHeaders.Contains(headerName, StringComparer.OrdinalIgnoreCase))
+            if (string.IsNullOrEmpty(headerName) ||
+                WellKnownHeaders.CommonHeaders.Contains(headerName, StringComparer.OrdinalIgnoreCase))
             {
                 return headerName;
             }

test/Microsoft.HttpRepl.Tests/Telemetry/Events/PreferenceEventTests.cs

@@ -0,0 +1,27 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.HttpRepl.Telemetry.Events;
+using Xunit;
+
+namespace Microsoft.HttpRepl.Tests.Telemetry.Events
+{
+    public class PreferenceEventTests
+    {
+        [Theory]
+        [InlineData("get", null)]
+        [InlineData("get", "")]
+        [InlineData("get", " ")]
+        [InlineData("get", "editor.command.default")]
+        [InlineData("get", "not.really.a.preference")]
+        [InlineData("set", null)]
+        [InlineData("set", "")]
+        [InlineData("set", " ")]
+        [InlineData("set", "editor.command.default")]
+        [InlineData("set", "not.really.a.preference")]
+        public void Constructor_DoesNotThrow(string getOrSet, string preferenceName)
+        {
+            PreferenceEvent preferenceEvent = new PreferenceEvent(getOrSet, preferenceName);
+        }
+    }
+}

test/Microsoft.HttpRepl.Tests/Telemetry/Events/SetHeaderEventTests.cs

@@ -0,0 +1,27 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.HttpRepl.Telemetry.Events;
+using Xunit;
+
+namespace Microsoft.HttpRepl.Tests.Telemetry.Events
+{
+    public class SetHeaderEventTests
+    {
+        [Theory]
+        [InlineData(null, false)]
+        [InlineData("", false)]
+        [InlineData(" ", false)]
+        [InlineData("Content-Type", false)]
+        [InlineData("X-Custom-Header", false)]
+        [InlineData(null, true)]
+        [InlineData("", true)]
+        [InlineData(" ", true)]
+        [InlineData("Content-Type", true)]
+        [InlineData("X-Custom-Header", true)]
+        public void Constructor_DoesNotThrow(string headerName, bool isValueEmpty)
+        {
+            SetHeaderEvent preferenceEvent = new SetHeaderEvent(headerName, isValueEmpty);
+        }
+    }
+}