Add a benchmark for inserting / deleting at end of 9000-line file

benchmark/benchmark-suite.coffee

@@ -82,6 +82,10 @@ describe "editor.", ->
           editor.moveCursorToBeginningOfWord()
           editor.setCursorScreenPosition(endPosition)
 
+        benchmark "insert-delete", 10, ->
+          editor.insertText('x')
+          editor.backspace()
+
 describe "TokenizedBuffer.", ->
   describe "coffee-script-grammar.", ->
     [languageMode, buffer] = []