attachToWindow

Explicitly attaches current root LithoView.

With LithoTestRule.attachToRealWindow the view joins the host Activity's window. Otherwise it only runs Litho's attach bookkeeping, without the view ever joining a real ViewRootImpl, which is enough for most tests but leaves framework behavior that a real window gates unreachable: AccessibilityNodeInfo is populated for a View in one and left empty otherwise, including for a plain View with isClickable = true.