Merge pull request dotnet#448 from colombod/feature/nuget_loading_doe…

…s_not_complete

#r nuget now completes the operation even when is the only content of code submission

Microsoft.DotNet.Interactive.Jupyter.Tests/MagicCommandTests.cs

@@ -167,6 +167,7 @@ public async Task markdown_renders_markdown_content_as_html()
 
             await kernel.SendAsync(new SubmitCode(
                                        $"%%markdown\n\n# Topic!\nContent"));
+
 
             var formatted =
                 events

Microsoft.DotNet.Interactive.Tests/SubscribedList{T}.cs

@@ -4,24 +4,31 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Collections.Immutable;
 
 namespace Microsoft.DotNet.Interactive.Tests
 {
     public class SubscribedList<T> : IReadOnlyList<T>, IDisposable
     {
-        private readonly List<T> _list = new List<T>();
+        private ImmutableArray<T> _list = ImmutableArray<T>.Empty;
         private readonly IDisposable _subscription;
 
         public SubscribedList(IObservable<T> source)
         {
-            _subscription = source.Subscribe(x => _list.Add(x));
+            _subscription = source.Subscribe(x =>
+            {
+                _list = _list.Add(x);
+            });
         }
 
-        public IEnumerator<T> GetEnumerator() => _list.GetEnumerator();
+        public IEnumerator<T> GetEnumerator()
+        {
+            return ((IEnumerable<T>) _list).GetEnumerator();
+        }
 
         IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
 
-        public int Count => _list.Count;
+        public int Count => _list.Length;
 
         public T this[int index] => _list[index];
 

Microsoft.DotNet.Interactive/KernelBase.cs

@@ -199,6 +199,7 @@ private async Task HandleDirectivesAndSubmitCode(
                 }
                 else
                 {
+                    context.Complete();
                     return;
                 }
             }

WorkspaceServer.Tests/Kernel/CSharpKernelTests.cs

@@ -433,6 +433,45 @@ public async Task When_SubmitCode_command_adds_packages_to_csharp_kernel_then_Pa
                 .ContainSingle(e => e is CommandHandled);
         }
 
+        [Fact]
+        public async Task When_SubmitCode_command_only_adds_packages_to_csharp_kernel_then_CommandHandled_event_is_raised()
+        {
+            var kernel = new CompositeKernel
+            {
+                new CSharpKernel().UseNugetDirective()
+            };
+
+            var command = new SubmitCode("#r \"nuget:Microsoft.Extensions.Logging, 2.2.0\"");
+
+            var result = await kernel.SendAsync(command);
+
+            using var events = result.KernelEvents.ToSubscribedList();
+
+            events
+                .First()
+                .Should()
+                .Match(e => e is DisplayedValueProduced && ((DisplayedValueProduced)e).Value.ToString().Contains("Attempting to install"));
+
+            events
+                .Should()
+                .Contain(e => e is DisplayedValueUpdated);
+
+
+            events
+                .Should()
+                .ContainSingle(e => e is NuGetPackageAdded);
+
+            events.OfType<NuGetPackageAdded>()
+                .Single()
+                .PackageReference
+                .Should()
+                .BeEquivalentTo(new NugetPackageReference("Microsoft.Extensions.Logging", "2.2.0"));
+
+            events
+                .Should()
+                .ContainSingle(e => e is CommandHandled);
+        }
+
         [Fact]
         public async Task The_extend_directive_can_be_used_to_load_a_kernel_extension()
         {

WorkspaceServer/Kernel/CSharpKernelExtensions.cs

@@ -1,13 +1,9 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
-using System.Collections.Generic;
 using System.CommandLine;
 using System.CommandLine.Invocation;
-using System.IO;
-using System.Linq;
 using System.Threading.Tasks;
-using System.Threading.Tasks.Dataflow;
 using Microsoft.CodeAnalysis;
 using Microsoft.DotNet.Interactive;
 using Microsoft.DotNet.Interactive.Commands;