This tutorial suggests that rather than being a document, test strategy is a thought process. The outcome of the thinking might be a short or a long document, but most importantly, the strategy must address the needs of the participants inside the project as well as the customers of the product to be built. It needs to be appropriate to a short agile project or to a 1000 man-year development. It has to have the buy-in of stakeholders but most importantly, it must have value and be communicated.
The Business Story Method is supported by and largely documented in a book called "The Business Story Pocketbook" which is available for FREE DOWNLOAD or can be purchased from Gerrard Consulting (or other good booksellers).