Activates necessary document before running methods

Fixes #1771
Allows for unit tests in Word Templates.

Author: ThunderFrame

Rubberduck.VBEEditor/VBEHost/WordApp.cs

@@ -1,4 +1,6 @@
 using Microsoft.Vbe.Interop;
+using Microsoft.Office.Interop.Word;
+using System.Linq;
 
 namespace Rubberduck.VBEditor.VBEHost
 {
@@ -10,13 +12,35 @@ public WordApp(VBE vbe) : base(vbe, "Word") { }
         public override void Run(QualifiedMemberName qualifiedMemberName)
         {
             var call = GenerateMethodCall(qualifiedMemberName);
-            Application.Run(call);
+
+            ActivateProjectDocument(qualifiedMemberName);
+            //Prevent TE hanging should Application.Run fail
+            try
+            {
+                Application.Run(call);
+            }
+            //TODO - Let TestEngine know that the method failed
+            catch { };
         }
 
         protected virtual string GenerateMethodCall(QualifiedMemberName qualifiedMemberName)
         {
             var moduleName = qualifiedMemberName.QualifiedModuleName.Component.Name;
             return string.Concat(moduleName, ".", qualifiedMemberName.MemberName);
         }
+
+        protected virtual void ActivateProjectDocument(QualifiedMemberName qualifiedMemberName)
+        {
+            // Word requires that the document be active for Application.Run to find the target Method in scope.
+            // Check the project's document or a document referring to a project's template is active.
+            var activeDoc = Application.ActiveDocument;
+            var template = activeDoc.get_AttachedTemplate();
+            var targetDoc = Application.Documents.Cast<Document>()
+                    .FirstOrDefault(doc => doc.Name == qualifiedMemberName.QualifiedModuleName.ProjectDisplayName
+                                        || doc.get_AttachedTemplate().Name == qualifiedMemberName.QualifiedModuleName.ProjectDisplayName);
+            if (activeDoc != targetDoc) { 
+                targetDoc.Activate();
+            }
+        }
     }
 }