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diff --git a/tests/Properties/Delete.hs b/tests/Properties/Delete.hs
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+{-# LANGUAGE ScopedTypeVariables #-}
+module Properties.Delete where
+
+import Test.QuickCheck
+import Instances
+import Utils
+
+import XMonad.StackSet hiding (filter)
+
+-- ---------------------------------------------------------------------
+-- 'delete'
+
+-- deleting the current item removes it.
+prop_delete x =
+    case peek x of
+        Nothing -> True
+        Just i  -> not (member i (delete i x))
+    where _ = x :: T
+
+-- delete is reversible with 'insert'.
+-- It is the identiy, except for the 'master', which is reset on insert and delete.
+--
+prop_delete_insert (x :: T) =
+    case peek x of
+        Nothing -> True
+        Just n  -> insertUp n (delete n y) == y
+    where
+        y = swapMaster x
+
+-- delete should be local
+prop_delete_local (x :: T) =
+    case peek x of
+        Nothing -> True
+        Just i  -> hidden_spaces x == hidden_spaces (delete i x)
+
+-- delete should not affect focus unless the focused element is what is being deleted
+prop_delete_focus = do
+  -- There should be at least two windows. One in focus, and some to try and
+  -- delete (doesn't have to be windows on the current workspace).  We generate
+  -- our own, since we can't rely on NonEmptyWindowsStackSet returning one in
+  -- the argument with at least two windows.
+  x <- arbitrary `suchThat` \x' -> length (allWindows x') >= 2
+  w <- arbitraryWindow (NonEmptyWindowsStackSet x)
+       -- Make sure we pick a window that is NOT the currently focused
+       `suchThat` \w' -> Just w' /= peek x
+  return $ peek (delete w x) == peek x
+
+-- focus movement in the presence of delete:
+-- when the last window in the stack set is focused, focus moves `up'.
+-- usual case is that it moves 'down'.
+prop_delete_focus_end = do
+    -- Generate a StackSet with at least two windows on the current workspace.
+    x <- arbitrary `suchThat` \(x' :: T) -> length (index x') >= 2
+    let w = last (index x)
+        y = focusWindow w x -- focus last window in stack
+    return $ peek (delete w y) == peek (focusUp y)
+
+
+-- focus movement in the presence of delete:
+-- when not in the last item in the stack, focus moves down
+prop_delete_focus_not_end = do
+  x <- arbitrary
+       -- There must be at least two windows and the current focused is not the
+       -- last one in the stack.
+       `suchThat` \(x' :: T) ->
+         let currWins = index x'
+         in length (currWins) >= 2 && peek x' /= Just (last currWins)
+  -- This is safe, as we know there are >= 2 windows
+  let Just n = peek x
+  return $ peek (delete n x) == peek (focusDown x)