diff --git a/tests/RotateSome.hs b/tests/RotateSome.hs
new file mode 100644
index 00000000..6ca3b9bb
--- /dev/null
+++ b/tests/RotateSome.hs
@@ -0,0 +1,75 @@
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE FlexibleInstances #-}
+
+module RotateSome where
+
+import Test.QuickCheck (Arbitrary, Gen, arbitrary, choose, listOf, quickCheck)
+import Utils (applyN)
+import XMonad.StackSet (Stack (Stack), down, focus, integrate, up)
+import XMonad.Actions.RotateSome (rotateSome)
+
+instance Arbitrary (Stack Int) where
+  arbitrary = do
+    foc   <- arbNat
+    ups   <- listOf arbNat
+    downs <- listOf arbNat
+    pure (Stack foc ups downs)
+
+arbNat :: Gen Int
+arbNat = fmap abs arbitrary
+
+newtype Divisor = Divisor Int deriving Show
+instance Arbitrary Divisor where
+  arbitrary = Divisor <$> choose (1, 5)
+
+isMultOf :: Int -> Int -> Bool
+x `isMultOf` n = (x `rem` n) == 0
+
+-- Total number of elements does not change.
+prop_rotate_some_length (Divisor d) (stk :: Stack Int) =
+  length (integrate stk) == length (integrate $ rotateSome (`isMultOf` d) stk)
+
+-- Applying rotateSome N times completes a cycle, where N is the number of
+-- elements that satisfy the predicate.
+prop_rotate_some_cycle (Divisor d) (stk :: Stack Int) =
+  stk == applyN (Just n) (rotateSome (`isMultOf` d)) stk
+  where
+    n = length $ filter (`isMultOf` d) (integrate stk)
+
+-- Elements that do not satisfy the predicate remain anchored in place.
+prop_rotate_some_anchors (Divisor d) (stk :: Stack Int) =
+  all check $
+    zip
+      (integrate stk)
+      (integrate $ rotateSome (`isMultOf` d) stk)
+  where
+    check (before, after) = (before `isMultOf` d) || before == after
+
+-- Elements that satisfy the predicate rotate by one position.
+prop_rotate_some_rotate (Divisor d) (stk :: Stack Int) =
+  drop 1 before ++ take 1 before == after
+  where
+    before = filter p (integrate stk)
+    after = filter p (integrate $ rotateSome p stk)
+    p = (`isMultOf` d)
+
+-- Focus position is preserved.
+prop_rotate_some_focus (Divisor d) (stk :: Stack Int) =
+  length (up stk) == length (up $ rotateSome (`isMultOf` d) stk)
+
+main :: IO ()
+main = do
+  putStrLn "Testing rotateSome length"
+  quickCheck prop_rotate_some_length
+
+  putStrLn "Testing rotateSome cycle"
+  quickCheck prop_rotate_some_cycle
+
+  putStrLn "Testing rotateSome anchors"
+  quickCheck prop_rotate_some_anchors
+
+  putStrLn "Testing rotateSome rotate"
+  quickCheck prop_rotate_some_rotate
+
+  putStrLn "Testing rotateSome focus"
+  quickCheck prop_rotate_some_focus