So, in the interest of sharing tricks I've learned, one I've come across is how to elegantly implement dashboard-style tables.
Dashboard-style tables are those where each row has a lot of interactivity, e.g. a user can start/stop/cancel the entity in the row, see the icons change, and other various UI things that you generally want to have under test in presenters.
For awhile, I was stumped because most GWT MVP tables favor data-style tables, where the focus is more on efficiently displaying 100s/1000s of rows of basically non-interactive data. There are a few counter examples, but none I had seen got to the point of pushing testable HasXxx interfaces back into a presenter for business logic to hook up to.
I finally got a suitable solution by realizing that each row is essentially its own view, and so instantiating a new RowXxxPresenter for each domain object in the value. This means there is a RowXxxView, which can expose all the HasXxx interfaces it wants to the presenter. And the RowXxxPresenterTest becomes a treat to write.
For more details and code examples, please jump over to the more elaborate post over on my personal blog.