QtTesting's own `currentChanged` command aborts on a one-element row list, so
pqWidgetTestEventPlayer drives views itself:
- selectRow selects a row through the selection model, the whole row, without a
mouse event
- clickRow left-clicks the centre of a cell, so the view's own handlers run
- doubleClickRow double-clicks it, for views whose double click acts
A tree addresses a row by the path of rows leading to it ("2/0" is the first
child of the third top-level row), and a click opens a collapsed path first.
Rows are model rows, so a filtered or sorted model counts the rows it shows.
Asserting what a command did needs QtTesting's check players, which the XML
source never reached: it marked every event an action, so `modelRowCount` was
rejected as unknown. An event now carries `type="check"` to be played as a
check.
Testing/item_view_test.xml drives the grouped settings navigation through
selectRow and clickRow and asserts the page stack followed.
Testing/deck_editor_double_click_test.xml proves the difference between the two
clicks: a single click on a card database row only selects it, a double click
adds the card to the deck.
