diff --git a/README.md b/README.md
index b37a2bd..227a59d 100644
--- a/README.md
+++ b/README.md
@@ -37,7 +37,8 @@ Available options:
     - [x] With different formats
   - [x] Add unit tests(HUnit)
   - [x] Remove "error" on parse issues, replace with "Maybe"
-  - [ ] Add -Weverything flag
+  - [x] Adding quickcheck testing(how to model strftime/log file inputs)
+  - [x] Add -Werror flag
   - [ ] `fileembed` with actual data + setup of regression tests
   - [ ] Add Github CI (optional)
 - [ ] Checkpoint 3: Performance
@@ -45,7 +46,6 @@ Available options:
   - [ ] Use heap for low memory consumption/Use streaming library
   - [ ] Benchmarks(optional)
 - [ ] Checkpoint 4: Stretch goals
-  - [ ] Adding quickcheck testing(how to model strftime/log file inputs)
   - [ ] Pull in remote files
   - [ ] Terminal coloring
     - [ ] Filename prefixing in output
diff --git a/loggy.cabal b/loggy.cabal
index 08bd62e..6a4a86a 100644
--- a/loggy.cabal
+++ b/loggy.cabal
@@ -19,6 +19,7 @@ common common-options
                  -Wincomplete-uni-patterns
                  -Wincomplete-record-updates
                  -Wredundant-constraints
+                 -Werror
   default-language:    Haskell2010
 
 library
@@ -42,6 +43,8 @@ test-suite loggy-test
   other-modules: Test.LoggyCore
   build-depends:       loggy
                      , hspec ^>= 2.7.4
+                     , hspec-hedgehog
+                     , hedgehog
   ghc-options:         -threaded
                        -rtsopts
                        -with-rtsopts=-N  
diff --git a/test/Test/LoggyCore.hs b/test/Test/LoggyCore.hs
index 0589522..3eb799d 100644
--- a/test/Test/LoggyCore.hs
+++ b/test/Test/LoggyCore.hs
@@ -1,7 +1,14 @@
 module Test.LoggyCore (loggycore) where
 
 import Test.Hspec (shouldBe, Spec, describe, it)
+import Test.Hspec.Hedgehog (hedgehog, (===), forAll, Gen)
 import Data.Time
+import Data.Time.Clock.System
+import qualified Hedgehog.Range as Range
+import qualified Hedgehog.Gen as Gen
+import Data.List (sort)
+import Control.Monad (msum)
+import Data.Maybe (catMaybes)
 
 import LoggyCore
 
@@ -30,14 +37,21 @@ loggycore = describe "LoggyCoreTest" $ do
     mergeLogLinesTest
 
 extractTimestampTest :: Spec
-extractTimestampTest = describe "LoggyCoreTest: extractTimestamp" $ do
+extractTimestampTest = describe "LoggyCoreTest: extractTimestampTest" $ do
     it "simpleTimestamp" $ extractTsHelper inputTime `shouldBe` inputDiffTime
     it "simpleTimestampWithSpaces" $ extractTsHelper (inputTimeWith " ") `shouldBe` inputDiffTime
     it "simpleTimestampWithExtraChars" $ extractTsHelper (inputTimeWith " random extra chars") `shouldBe` inputDiffTime   
     it "simpleTimestampWithRepeatedTimestamp" $ extractTsHelper (inputTimeWith $ " " ++ inputTime) `shouldBe` inputDiffTime
     it "invalidLogLine" $ extractTsHelper "invalid input" `shouldBe` Nothing
-        where
-            extractTsHelper tsLog = utctDayTime <$> extractTimestamp dateFormat tsLog
+    it "extractTimestampPropertyTest" $ hedgehog $ do
+        logText <- forAll $ Gen.string (Range.linear 0 1000) Gen.ascii 
+        unixTimeSeconds <- forAll $ Gen.int64 (Range.linear 0 1000)
+        let utcTime = systemToUTCTime $ MkSystemTime unixTimeSeconds 0
+        let utcTimeStr = formatTime defaultTimeLocale  dateFormat utcTime
+        let logLine = utcTimeStr ++ " " ++ logText
+        Just utcTime === extractTimestamp dateFormat logLine
+    where
+        extractTsHelper tsLog = utctDayTime <$> extractTimestamp dateFormat tsLog 
 
 mergeLogLinesTest :: Spec
 mergeLogLinesTest = describe "LoggyCoreTest: mergeLogLines" $ do
@@ -64,4 +78,45 @@ mergeLogLinesTest = describe "LoggyCoreTest: mergeLogLines" $ do
     it "invalidLogLine" $ testMergeLogs dateFormat [[" invalid log line"]]
                 `shouldBe` MkMergeResult [] InvalidLogLine
     it "invalidLogLines" $ testMergeLogs dateFormat [[" invalid log line", inputTimeWith " from file 1"]]
-                    `shouldBe` MkMergeResult [inputTimeWith " from file 1"] InvalidLogLine
\ No newline at end of file
+                    `shouldBe` MkMergeResult [inputTimeWith " from file 1"] InvalidLogLine
+    it "mergeLogLinesPropertyTest" $ hedgehog $ do
+        numFiles <- forAll $ Gen.int (Range.linear 1 10)
+        fileDateFormats <- forAll $ genDateFormats numFiles
+        logFiles <- forAll $ mapM genFile fileDateFormats
+        let MkMergeResult mergedLines mergeStatus = mergeLogLines (zip fileDateFormats logFiles)
+        length mergedLines === sum (map length logFiles)
+        mergeStatus === NoWarning
+        let maybeTsPerLogLine = map (dateFormats `extractTimestamp'`) mergedLines 
+        let tsPerLogLine = catMaybes maybeTsPerLogLine
+        length tsPerLogLine === length mergedLines
+        isSorted tsPerLogLine === True
+        where
+            dateFormats :: [DateFormat]
+            dateFormats = ["%H:%M:%S", "%H-%M-%S", "%H/%M/%S", "%H.%M.%S"]
+            genDateFormats ::Int -> Gen [DateFormat]
+            genDateFormats numFiles = Gen.list (Range.singleton numFiles) (Gen.element dateFormats)
+            genFile :: DateFormat -> Gen LogFileLines
+            genFile dFormat = do
+                numLogLines <- Gen.int (Range.linear 0 100)
+                logTxtLines <- Gen.list (Range.singleton numLogLines) (Gen.string (Range.linear 0 100) Gen.ascii)
+                logTsLst <- genSortedDates numLogLines
+                let logTsFormattedLst = map (formatTime defaultTimeLocale dFormat) logTsLst
+                let logLines = zipWith (\ts logLine -> ts ++ " " ++ logLine) logTsFormattedLst logTxtLines
+                return logLines
+            genSortedDates :: Int -> Gen [UTCTime]
+            genSortedDates numLines = do
+                unixTsLst <- Gen.list (Range.singleton numLines) (Gen.int64 (Range.linear 0 1000))
+                let sortedUnixTsLst = sort unixTsLst
+                let utcTimeLst = map (\ts -> systemToUTCTime $ MkSystemTime ts 0) sortedUnixTsLst
+                return utcTimeLst    
+            extractTimestamp' :: [DateFormat] -> LogLine -> Maybe UTCTime
+             -- Brute force try all formats till one matches
+            extractTimestamp' dFs logLine = tsForLogLine
+                where
+                    tsForLogLine = msum tsPerDateFormat
+                    tsPerDateFormat = map (`extractTimestamp` logLine) dFs
+            isSorted :: (Ord a) => [a] -> Bool
+            isSorted []       = True
+            isSorted [_]      = True
+            isSorted (x:y:xs) = x <= y && isSorted (y:xs)
+