Add test

src/Compilers/CSharp/Test/Syntax/Syntax/SyntaxListTests.cs

@@ -226,9 +226,13 @@ public void AddEmptySyntaxList()
         }
 
         [Fact]
-        public void AddNamespaceAttributeLists()
+        public void AddNamespaceAttributeListsAndModifiers()
         {
             var declaration = SyntaxFactory.NamespaceDeclaration(SyntaxFactory.ParseName("M"));
+
+            Assert.True(declaration.AttributeLists.Count == 0);
+            Assert.True(declaration.Modifiers.Count == 0);
+
             declaration = declaration.AddAttributeLists(new[]
             {
                 SyntaxFactory.AttributeList(SyntaxFactory.SingletonSeparatedList(
@@ -236,6 +240,12 @@ public void AddNamespaceAttributeLists()
             });
 
             Assert.True(declaration.AttributeLists.Count == 1);
+            Assert.True(declaration.Modifiers.Count == 0);
+
+            declaration = declaration.AddModifiers(SyntaxFactory.Token(SyntaxKind.PublicKeyword));
+
+            Assert.True(declaration.AttributeLists.Count == 1);
+            Assert.True(declaration.Modifiers.Count == 1);
         }
 
         [Fact]