More hardening of the completion test

src/Razor/test/Microsoft.VisualStudio.Razor.IntegrationTests/CompletionIntegrationTests.cs

@@ -2,6 +2,7 @@
 // Licensed under the MIT license. See License.txt in the project root for license information.
 
 using System;
+using System.Diagnostics;
 using System.Linq;
 using System.Threading.Tasks;
 using Roslyn.Test.Utilities;
@@ -212,7 +213,8 @@ private void IncrementCount()
                 """,
             search: "</PageTitle>",
             stringsToType: ["{ENTER}", "{ENTER}", "<", "s", "p", "a"],
-            commitChar: '>');
+            commitChar: '>',
+            "span");
     }
 
     [IdeFact]
@@ -253,7 +255,7 @@ private void IncrementCount()
             stringsToType: ["{ENTER}", "{ENTER}", "m", "y", "C", "u", "r"]);
     }
 
-    private async Task VerifyTypeAndCommitCompletionAsync(string input, string output, string search, string[] stringsToType, char? commitChar = null)
+    private async Task VerifyTypeAndCommitCompletionAsync(string input, string output, string search, string[] stringsToType, char? commitChar = null, string? expectedSelectedItemLabel = null)
     {
         await TestServices.SolutionExplorer.AddFileAsync(
             RazorProjectConstants.BlazorProjectName,
@@ -270,7 +272,14 @@ await TestServices.SolutionExplorer.AddFileAsync(
             TestServices.Input.Send(stringToType);
         }
 
-        await CommitCompletionAndVerifyAsync(output, commitChar);
+        if (expectedSelectedItemLabel is not null)
+        {
+            await CommitCompletionAndVerifyAsync(output, expectedSelectedItemLabel, commitChar);
+        }
+        else
+        {
+            await CommitCompletionAndVerifyAsync(output, commitChar);
+        }
     }
 
     [IdeFact]
@@ -457,4 +466,41 @@ private async Task CommitCompletionAndVerifyAsync(string expected, char? commitC
         // tests allow for it as long as the content is correct
         AssertEx.AssertEqualToleratingWhitespaceDifferences(expected, text);
     }
+
+    private async Task CommitCompletionAndVerifyAsync(string expected, string expectedSelectedItemLabel, char? commitChar = null)
+    {
+        // Actually open completion UI and wait for it have selected item we are interested in
+        var session = await TestServices.Editor.OpenCompletionSessionAndWaitForItemAsync(TimeSpan.FromSeconds(10), expectedSelectedItemLabel, HangMitigatingCancellationToken);
+
+        Assert.NotNull(session);
+        if (commitChar.HasValue)
+        {
+            // Commit using the specified commit character
+            session.Commit(commitChar.Value, HangMitigatingCancellationToken);
+
+            // session.Commit call above commits as if the commit character was typed,
+            // but doesn't actually insert the character into the buffer.
+            // So we still need to insert the character into the buffer ourselves.
+            TestServices.Input.Send(commitChar.Value.ToString());
+        }
+        else
+        {
+            Assert.True(session.CommitIfUnique(HangMitigatingCancellationToken));
+        }
+
+        var textView = await TestServices.Editor.GetActiveTextViewAsync(HangMitigatingCancellationToken);
+
+        var stopwatch = new Stopwatch();
+        string text;
+        while ((text = textView.TextBuffer.CurrentSnapshot.GetText()) != expected && stopwatch.ElapsedMilliseconds < 10000)
+        {
+            // Text might get updated *after* completion by something like auto-insert, so wait for the desired text
+            await Task.Delay(100);
+        }
+
+        // Snippets may have slight whitespace differences due to line endings. These
+        // tests allow for it as long as the content is correct
+        Assert.Equal(expected, text);
+    }
+
 }

src/Razor/test/Microsoft.VisualStudio.Razor.IntegrationTests/InProcess/EditorInProcess_Completion.cs

@@ -55,4 +55,43 @@ public async Task DismissCompletionSessionsAsync(CancellationToken cancellationT
 
         return session;
     }
+
+    /// <summary>
+    /// Open completion pop-up window UI and wait for the specified item to be present selected
+    /// </summary>
+    /// <param name="timeOut"></param>
+    /// <param name="selectedItemLabel"></param>
+    /// <param name="cancellationToken"></param>
+    /// <returns>Completion session that has matching selected item, or null otherwise</returns>
+    public async Task<IAsyncCompletionSession?> OpenCompletionSessionAndWaitForItemAsync(TimeSpan timeOut, string selectedItemLabel, CancellationToken cancellationToken)
+    {
+        await JoinableTaskFactory.SwitchToMainThreadAsync(cancellationToken);
+
+        // Returns completion session that might or might not be visible in the IDE
+        var session = await WaitForCompletionSessionAsync(timeOut, cancellationToken);
+
+        if (session is null)
+        {
+            return null;
+        }
+
+        var textView = await GetActiveTextViewAsync(cancellationToken);
+        var stopWatch = Stopwatch.StartNew();
+
+        // Actually open the completion pop-up window and force visible items to be computed or re-computed
+        session.OpenOrUpdate(new CompletionTrigger(CompletionTriggerReason.Insertion, textView.TextSnapshot), textView.Caret.Position.BufferPosition, cancellationToken);
+        while (session.GetComputedItems(cancellationToken).SelectedItem?.DisplayText != selectedItemLabel)
+        {
+            if (stopWatch.ElapsedMilliseconds >= timeOut.TotalMilliseconds)
+            {
+                return null;
+            }
+
+            await Task.Delay(TimeSpan.FromMilliseconds(100), cancellationToken);
+
+            session.OpenOrUpdate(new CompletionTrigger(CompletionTriggerReason.Insertion, textView.TextSnapshot), textView.Caret.Position.BufferPosition, cancellationToken);
+        }
+
+        return session;
+    }
 }