diff --git a/Unique.cabal b/Unique.cabal
--- a/Unique.cabal
+++ b/Unique.cabal
@@ -1,6 +1,6 @@
 name:                Unique
 
-version:             0.4.7
+version:             0.4.7.1
 
 synopsis:            It provides the functionality like unix "uniq" utility
 description:         Library provides the functions to find unique and duplicate elements in the list
@@ -38,8 +38,9 @@
                      , IsUnique
                      , RepeatedBy
                      , SortUniq
+                     , AllUnique
 
-  build-depends:       base >=4.0 && < 4.10
+  build-depends:       base >=4.0 && < 5
                      , hspec
                      , containers
                      , QuickCheck
diff --git a/tests/AllUnique.hs b/tests/AllUnique.hs
new file mode 100644
--- /dev/null
+++ b/tests/AllUnique.hs
@@ -0,0 +1,33 @@
+module AllUnique where
+
+import Test.Hspec
+import Test.QuickCheck
+import Control.Exception (evaluate)
+import Data.List (nub)
+
+import Data.List.Unique
+
+
+allUnique' :: Eq a => [a] -> Bool
+allUnique' ls = (nub ls) == ls
+
+allUniqueTests :: SpecWith ()
+allUniqueTests =
+  describe "Data.List.Unique.allUnique" $ do
+  it "allUnique: returns True with empty list" $ do
+    allUnique "" `shouldBe` True
+
+  it "allUnique: returns False when some element is not unique" $ do
+    allUnique "foo bar" `shouldBe` False
+
+  it "allUnique: returns True when list does not have duplicates" $ do
+    allUnique ([1..1000] :: [Int]) `shouldBe` True
+
+  it "allUnique: fails if list consist of duplicate elements and 'undefined' after them" $ do
+    evaluate (allUnique ['a', 'a', undefined] )
+      `shouldThrow`
+      errorCall "Prelude.undefined"
+
+  it "allUnique: Test the function using slower analog and random data" $
+    property $
+    \ xs -> (allUnique' (xs :: String)) == (allUnique xs)