Extract test helper

src/EditorFeatures/Test2/IntelliSense/CSharpCompletionCommandHandlerTests.vb

@@ -3007,11 +3007,7 @@ class C
                         "service"
                     }
 
-                Dim items = state.CurrentCompletionPresenterSession.CompletionItems
-                Assert.Equal(expectedOrder.Count, items.Count)
-                For i = 0 To expectedOrder.Count - 1
-                    Assert.Equal(expectedOrder(i), items(i).DisplayText)
-                Next
+                state.AssertItemsInOrder(expectedOrder)
             End Using
         End Function
     End Class

src/EditorFeatures/TestUtilities2/Intellisense/TestState.vb

@@ -236,6 +236,15 @@ Namespace Microsoft.CodeAnalysis.Editor.UnitTests.IntelliSense
                                        Function(i) i.DisplayText = v))
         End Function
 
+        Public Function AssertItemsInOrder(expectedOrder As String()) As Boolean
+            AssertNoAsynchronousOperationsRunning()
+            Dim items = CurrentCompletionPresenterSession.CompletionItems
+            Assert.Equal(expectedOrder.Count, items.Count)
+            For i = 0 To expectedOrder.Count - 1
+                Assert.Equal(expectedOrder(i), items(i).DisplayText)
+            Next
+        End Function
+
         Public Async Function AssertSelectedCompletionItem(
                                Optional displayText As String = Nothing,
                                Optional description As String = Nothing,