diff --git a/Makefile b/Makefile
index d8d2a69..401ce0c 100644
--- a/Makefile
+++ b/Makefile
@@ -3,8 +3,4 @@ all:
 	cabal build
 
 filetest:
-	./dnp -f tests/ex1.dnp
-	./dnp -f tests/ex2.dnp
-	./dnp -f tests/ex3.dnp
-	./dnp -f tests/ex4.dnp
-	./dnp -f tests/ex5.dnp
+	./test
diff --git a/src/UnitTests.hs b/src/UnitTests.hs
deleted file mode 100644
index 0e0097b..0000000
--- a/src/UnitTests.hs
+++ /dev/null
@@ -1,267 +0,0 @@
-module UnitTests where
-
-import Test.HUnit
-import FlowController
-import qualified Set
-import FlowControllerLang
-import Base
-import qualified TokenBucket as TB
--- import EmitFML
-
-instance AssertionPredicable (Maybe a) where
-  assertionPredicate Nothing = return False
-  assertionPredicate (Just _) = return True
-
-unexpectedState (Just _) = Nothing
-unexpectedState Nothing = Just emptyState
-
-foreverReq shareRef flow rd =
- Req shareRef flow 0 NoLimit rd True
-
-test1 = evalDNP $ do
-  createSpeakerM "arjun"
-
-test2 = evalDNP $ do
-  b <- createSpeakerM "root"
-  return (not b)
-
-test3 = evalDNP $ do
-  b1 <- createSpeakerM "arjun"
-  b2 <- createSpeakerM "adf"
-  return (b1 && b2)
-
-test4 = evalDNP $ do
-  b1 <- createSpeakerM "arjun"
-  b2 <- createSpeakerM "arjun"
-  return (b1 && not b2)
-
-test5 = evalDNP $ do
-  b1 <- createSpeakerM "arjun"
-  b2 <- giveReferenceM "root" rootShareRef "arjun"
-  return (b1 && b2)
-
-test6 = evalDNP $ do
-  b1 <- createSpeakerM "arjun"
-  let s = Share anyFlow (Set.singleton "root") emptyShareReq (DiscreteLimit 100)
-            False False TB.unlimited
-  b2 <- newShareM "root" rootShareRef "arjun-share" s
-  b3 <- giveReferenceM "root" "arjun-share" "arjun"
-  return (b1 && b2 && b3)
-
-frag1 limitForAdf = do
-  b1 <- createSpeakerM "arjun"
-  b2 <- createSpeakerM "adf"
-  let s = Share anyFlow (Set.singleton "root") emptyShareReq (DiscreteLimit 100)
-            False False TB.unlimited
-  b3 <- newShareM "root" rootShareRef "arjun-share" s 
-  b4 <- giveReferenceM "root" "arjun-share" "arjun"
-  let s' = Share anyFlow (Set.singleton "arjun") emptyShareReq (DiscreteLimit limitForAdf)
-            False False TB.unlimited
-  b5 <- newShareM "arjun" "arjun-share" "adf-share" s' 
-  b6 <- giveReferenceM "arjun" "adf-share" "adf"
-  return (b1 && b2 && b3 && b4 && b5 && b6)
-
-test7 = evalDNP $ do
-   b1 <- frag1 200
-   return (not b1)
-
-test8 = evalDNP $ do frag1 50
-
-test9 =  evalDNP $ do
-  b1 <- frag1 50
-  b2 <- giveReferenceM "arjun" "adf-share" "non user" 
-  return (b1 && not b2)
-
-  
-frag2 = do
-  let s = Share anyFlow (Set.singleton "root") emptyShareReq (DiscreteLimit 200)
-            True True TB.unlimited
-  b1 <- newShareM "root" rootShareRef "net0" s
-  return b1
-
-test10 = evalDNP $ do frag2
-
-test11 = evalDNP $ do
-  b1 <- frag2 
-  b2 <- requestM "root" (foreverReq "net0" anyFlow (ReqResv 300))
-  return (b1 && not b2)
-
-test12 = evalDNP $ do
-  b1 <- frag2
-  b2 <- requestM "root" (foreverReq rootShareRef anyFlow (ReqResv 300))
-  return (b1 && b2)
-
-test13 = evalDNP $ do
-  b1 <- frag2
-  b2 <- requestM "root" (foreverReq "net0" anyFlow (ReqResv 100))
-  b3 <- requestM "root" (foreverReq "net0" anyFlow (ReqResv 100))
-  return (b1 && b2 && b3)
-
-test14 = evalDNP $ do
-  b1 <- frag2
-  b2 <- requestM "root" (foreverReq "net0" anyFlow (ReqResv 100))
-  b3 <- requestM "root" (foreverReq "net0" anyFlow (ReqResv 100))
-  b4 <- requestM "root" (foreverReq "net0" anyFlow (ReqResv 100))
-  return (b1 && b2 && b3 && not b4)
-
-
-frag3 = do 
-  b1 <- frag2
-  b2 <- createSpeakerM "adf"
-  let s = Share anyFlow (Set.singleton "root") emptyShareReq (DiscreteLimit 150)
-            False False TB.unlimited
-  b3 <- newShareM "root" "net0" "adfShare" s
-  b4 <- giveReferenceM "root" "adfShare" "adf"
-  b5 <- requestM "adf" (foreverReq "adfShare" anyFlow (ReqResv 100))
-  return (b1 && b2 && b3 && b4 && b5)
-
-test15 = evalDNP $ do frag3
-
-test16 = evalDNP $ do
-  b1 <- frag3
-  b2 <- requestM "root" (foreverReq "net0" anyFlow (ReqResv 100))
-  return (b1 && b2)
-
-test16a = evalDNP $ do
-  b1 <- frag3
-  b2 <- requestM "root" (foreverReq "adfShare" anyFlow (ReqResv 50))
-  return (b1 && b2)
-
-test16b = evalDNP $ do
-  b1 <- frag3
-  b2 <- requestM "root" (foreverReq "adfShare" anyFlow (ReqResv 51))
-  return (b1 && not b2)
-
-test17 = evalDNP $ do
-  b1 <- frag3
-  b2 <- requestM "root" (foreverReq "net0" anyFlow (ReqResv 101))
-  return (b1 && not b2)
-
-test18 = evalDNP $ do
-  b1 <- frag3
-  b2 <- requestM "adf" (foreverReq "adfShare" anyFlow (ReqResv 51))
-  return (b1 && not b2)
-
-frag4 = do
-  b1 <- createSpeakerM "arjun"
-  let s = Share anyFlow (Set.singleton "root") emptyShareReq (DiscreteLimit 100)
-            False False TB.unlimited
-  b2 <- newShareM "root" rootShareRef "hadoop-share" s
-  b3 <- giveDefaultReferenceM "root" "hadoop-share"
-  b4 <- requestM "arjun" (foreverReq "hadoop-share" anyFlow (ReqResv 25))
-  return (b1 && b2 && b3 && b4)
-
-test19 = evalDNP $ do frag4
-
-test20 = evalDNP $ do
-  b1 <- frag4
-  b2 <- createSpeakerM "adf"
-  b3 <- requestM "adf" (foreverReq "hadoop-share" anyFlow (ReqResv 25))
-  return (b1 && b2 && b3)
-
-arjunFlow = anyFlow { flowSend = Set.singleton "arjun" }
-
-frag5 = do
-  b1 <- createSpeakerM "arjun"
-  let s = Share arjunFlow (Set.singleton "root") emptyShareReq (DiscreteLimit 100)
-            False False TB.unlimited
-  b2 <- newShareM "root" rootShareRef "arjun-share" s
-  b3 <- giveReferenceM "root" "arjun-share" "arjun"
-  b4 <- requestM "arjun" (foreverReq "arjun-share" arjunFlow (ReqResv 50))
-  s  <- currentRequestsM
-  let b5 = Set.fromList s == Set.singleton (
-                               foreverReq "arjun-share" arjunFlow (ReqResv 50))
-  return (b1 && b2 && b3 && b4 && b5)
-
-test21 = evalDNP $ frag5
-
-
-frag6 = do
-  b1 <- frag5
-  let arjunWebFlow = (arjunFlow { flowSrcPort = Set.singleton 80}) 
-  b2 <- requestM "arjun" (foreverReq "arjun-share" arjunWebFlow (ReqResv 50))
-  s  <- currentRequestsM
-  let b3 = Set.fromList s == Set.fromList [
-                           (foreverReq "arjun-share" arjunFlow  (ReqResv 50)),
-                           (foreverReq "arjun-share" arjunWebFlow (ReqResv 50))]
-  return (b1 && b2 && b3)
-
-test22 = evalDNP frag6
-
-test23 = evalDNP $ do
-  b1 <- frag5
-  b2 <- requestM "arjun" (foreverReq "arjun-share" anyFlow (ReqResv 50))
-  return (b1 && not b2)
-
-test24 = evalDNP $ do
-  b1 <- frag2 -- root creates net0 share
-  let req = Req rootShareRef anyFlow 0 (DiscreteLimit 10) (ReqResv 100) True
-  b2 <- requestM rootSpeaker req
-  s <- currentRequestsM
-  let b3 = s == [req]
-  tickM 5
-  s <- currentRequestsM
-  let b4 = s == [req]
-  tickM 2
-  s <- currentRequestsM
-  let b5 = s == [req]
-  tickM 4
-  s <- currentRequestsM
-  let b6 = s == []
-  return (b1 && b2 && b3 && b4 && b5 && b6)
-
-test25 = evalDNP $ do
-  b1 <- frag2
-  let req = Req rootShareRef anyFlow 5 (DiscreteLimit 10) (ReqResv 100) True
-  b2 <- requestM rootSpeaker req
-  s <- currentRequestsM
-  let b3 = s == []
-  tickM 4
-  s <- currentRequestsM
-  let b4 = s == []
-  tickM 1
-  s <- currentRequestsM
-  let b5 = s == [req]
-  tickM 4
-  s <- currentRequestsM
-  let b6 = s == [req]
-  tickM 1
-  s <- currentRequestsM
-  let b7 = s == []
-  return (b1 && b2 && b3 && b4 && b5 && b6 && b7)
-  
-
-allTests = TestList
-  [ test1 ~? "cannot create speaker"
-  , test2 ~? "duplicate speaker"
-  , test3 ~? "cannot create two speakers"
-  , test4 ~? "duplicate speaker arjun"
-  , test5 ~? "giving root-reference"
-  , test6 ~? "giving user-restricted reference"
-  , test7 ~? "cannot increase limit on a reference"
-  , test8 ~? "can decrease limit on a reference"
-  , test9 ~? "giving to non-existant user"
-  , test10 ~? "create physical share"
-  , test11 ~? "cannot exceed quota"
-  , test12 ~? "it is silly to reserve from unlimited share"
-  , test13 ~? "reserve to limit"
-  , test14 ~? "reserve beyond limit"
-  , test15 ~? "adf can reserve"
-  , test16 ~? "reserve to limit in separate shares"
-  , test16a ~? "root reserve from ADF share"
-  , test16b ~? "root reserve too much from ADF share"
-  , test17 ~? "cannot give root what he wants"
-  , test18 ~? "exceeded limit on subshare"
-  , test19 ~? "use default reference"
-  , test20 ~? "use default reference with new user"
-  , test21 ~? "put flow restrictions on subshare"
-  , test22 ~? "reserve with more restricted flow than restriction on share"
-  , test23 ~? "cannot reserve with less restricted flow than restr. on share"
-  , test24 ~? "reservation should expire"
-  , test25 ~? "reservation in the future"
-  ]
-
-main :: IO ()
-main = do
-  runTestTT allTests
-  return ()
diff --git a/test b/test
new file mode 100755
index 0000000..a0a9479
--- /dev/null
+++ b/test
@@ -0,0 +1,12 @@
+#!/bin/bash
+
+for file in tests/*.dnp
+do
+  echo -en "\rTest $file ... "
+  ./dnp -f $file
+  tput el1
+done
+
+
+
+echo "Testing complete."
diff --git a/tests/t1.dnp b/tests/t1.dnp
new file mode 100644
index 0000000..9b6c407
--- /dev/null
+++ b/tests/t1.dnp
@@ -0,0 +1 @@
+True <- root : AddUser arjun.
diff --git a/tests/t10.dnp b/tests/t10.dnp
new file mode 100644
index 0000000..68a37a2
--- /dev/null
+++ b/tests/t10.dnp
@@ -0,0 +1 @@
+True <- root : NewShare net0 for (*) [reserve <= 200] on rootShare.
diff --git a/tests/t11.dnp b/tests/t11.dnp
new file mode 100644
index 0000000..3000c35
--- /dev/null
+++ b/tests/t11.dnp
@@ -0,0 +1,2 @@
+True <- root : NewShare net0 for (*) [reserve <= 200] on rootShare.
+False <- root : reserve(*) = 300 on net0.
diff --git a/tests/t12.dnp b/tests/t12.dnp
new file mode 100644
index 0000000..b084a51
--- /dev/null
+++ b/tests/t12.dnp
@@ -0,0 +1,2 @@
+True <- root : NewShare net0 for (*) [reserve <= 200] on rootShare.
+True <- root : reserve(*) = 300 on rootShare.
diff --git a/tests/t13.dnp b/tests/t13.dnp
new file mode 100644
index 0000000..fd71db3
--- /dev/null
+++ b/tests/t13.dnp
@@ -0,0 +1,3 @@
+True <- root : NewShare net0 for (*) [reserve <= 200] on rootShare.
+True <- root : reserve(*) = 100 on net0.
+True <- root : reserve(*) = 100 on net0.
diff --git a/tests/t14.dnp b/tests/t14.dnp
new file mode 100644
index 0000000..ef06942
--- /dev/null
+++ b/tests/t14.dnp
@@ -0,0 +1,4 @@
+True <- root : NewShare net0 for (*) [reserve <= 200] on rootShare.
+True <- root : reserve(*) = 100 on net0.
+True <- root : reserve(*) = 100 on net0.
+False <- root : reserve(*) = 100 on net0.
diff --git a/tests/t15.dnp b/tests/t15.dnp
new file mode 100644
index 0000000..7d24573
--- /dev/null
+++ b/tests/t15.dnp
@@ -0,0 +1,5 @@
+True <- root : NewShare net0 for (*) [reserve <= 200] on rootShare.
+True <- root : AddUser adf.
+True <- root : NewShare adfShare for (*) [reserve <= 150] on net0.
+True <- root : Grant adfShare to adf.
+True <- adf : reserve(*) = 100 on adfShare.
diff --git a/tests/t16.dnp b/tests/t16.dnp
new file mode 100644
index 0000000..a75fdef
--- /dev/null
+++ b/tests/t16.dnp
@@ -0,0 +1,6 @@
+True <- root : NewShare net0 for (*) [reserve <= 200] on rootShare.
+True <- root : AddUser adf.
+True <- root : NewShare adfShare for (*) [reserve <= 150] on net0.
+True <- root : Grant adfShare to adf.
+True <- adf : reserve(*) = 100 on adfShare.
+True <- root : reserve(*) = 100 on net0.
diff --git a/tests/t16a.dnp b/tests/t16a.dnp
new file mode 100644
index 0000000..58edd65
--- /dev/null
+++ b/tests/t16a.dnp
@@ -0,0 +1,6 @@
+True <- root : NewShare net0 for (*) [reserve <= 200] on rootShare.
+True <- root : AddUser adf.
+True <- root : NewShare adfShare for (*) [reserve <= 150] on net0.
+True <- root : Grant adfShare to adf.
+True <- adf : reserve(*) = 100 on adfShare.
+True <- root : reserve(*) = 50 on adfShare.
diff --git a/tests/t16b.dnp b/tests/t16b.dnp
new file mode 100644
index 0000000..9e3164a
--- /dev/null
+++ b/tests/t16b.dnp
@@ -0,0 +1,6 @@
+True <- root : NewShare net0 for (*) [reserve <= 200] on rootShare.
+True <- root : AddUser adf.
+True <- root : NewShare adfShare for (*) [reserve <= 150] on net0.
+True <- root : Grant adfShare to adf.
+True <- adf : reserve(*) = 100 on adfShare.
+False <- root : reserve(*) = 51 on adfShare.
diff --git a/tests/t17.dnp b/tests/t17.dnp
new file mode 100644
index 0000000..38a413c
--- /dev/null
+++ b/tests/t17.dnp
@@ -0,0 +1,6 @@
+True <- root : NewShare net0 for (*) [reserve <= 200] on rootShare.
+True <- root : AddUser adf.
+True <- root : NewShare adfShare for (*) [reserve <= 150] on net0.
+True <- root : Grant adfShare to adf.
+True <- adf : reserve(*) = 100 on adfShare.
+False <- root : reserve(*) = 101 on net0.
diff --git a/tests/t18.dnp b/tests/t18.dnp
new file mode 100644
index 0000000..62402ef
--- /dev/null
+++ b/tests/t18.dnp
@@ -0,0 +1,6 @@
+True <- root : NewShare net0 for (*) [reserve <= 200] on rootShare.
+True <- root : AddUser adf.
+True <- root : NewShare adfShare for (*) [reserve <= 150] on net0.
+True <- root : Grant adfShare to adf.
+True <- adf : reserve(*) = 100 on adfShare.
+False <- adf : reserve(*) = 51 on adfShare.
diff --git a/tests/t19.dnp b/tests/t19.dnp
new file mode 100644
index 0000000..9d81f8b
--- /dev/null
+++ b/tests/t19.dnp
@@ -0,0 +1,4 @@
+True <- root : AddUser arjun.
+True <- root : NewShare hadoopShare for (*) [reserve<=100] on rootShare.
+True <- root : GrantDefault hadoopShare.
+True <- arjun : reserve(*) = 25 on hadoopShare.
diff --git a/tests/t2.dnp b/tests/t2.dnp
new file mode 100644
index 0000000..b25a3a0
--- /dev/null
+++ b/tests/t2.dnp
@@ -0,0 +1 @@
+False <- root : AddUser root.
diff --git a/tests/t20.dnp b/tests/t20.dnp
new file mode 100644
index 0000000..1be97cd
--- /dev/null
+++ b/tests/t20.dnp
@@ -0,0 +1,6 @@
+True <- root : AddUser arjun.
+True <- root : NewShare hadoopShare for (*) [reserve<=100] on rootShare.
+True <- root : GrantDefault hadoopShare.
+True <- arjun : reserve(*) = 25 on hadoopShare.
+True <- root : AddUser adf.
+True <- adf : reserve(*) = 25 on hadoopShare.
diff --git a/tests/t21.dnp b/tests/t21.dnp
new file mode 100644
index 0000000..14d1931
--- /dev/null
+++ b/tests/t21.dnp
@@ -0,0 +1,4 @@
+True <- root : AddUser arjun.
+True <- root : NewShare arjunShare for (user=arjun) [reserve <= 100] on rootShare.
+True <- root : Grant arjunShare to arjun.
+True <- arjun : reserve (user=arjun) = 50 on arjunShare.
diff --git a/tests/t22.dnp b/tests/t22.dnp
new file mode 100644
index 0000000..f7b7c4b
--- /dev/null
+++ b/tests/t22.dnp
@@ -0,0 +1,13 @@
+True <- root : AddUser arjun.
+True <- root : NewShare arjunShare for (user=arjun) [reserve <= 100] on rootShare.
+True <- root : Grant arjunShare to arjun.
+True <- arjun : reserve (user=arjun) = 50 on arjunShare.
+True <- arjun : reserve(user=arjun,app=80) = 50 on arjunShare.
+/* TODO: the in-Haskell test checked that
+
+  Set.fromList s == Set.fromList [
+                  (foreverReq "arjun-share" arjunFlow  (ReqResv 50)),
+                  (foreverReq "arjun-share" arjunWebFlow (ReqResv 50))]
+  
+  We can do this (or something similar) once we return the free/busy schedule.
+*/
diff --git a/tests/t23.dnp b/tests/t23.dnp
new file mode 100644
index 0000000..b0da96a
--- /dev/null
+++ b/tests/t23.dnp
@@ -0,0 +1,5 @@
+True <- root : AddUser arjun.
+True <- root : NewShare arjunShare for (user=arjun) [reserve <= 100] on rootShare.
+True <- root : Grant arjunShare to arjun.
+True <- arjun : reserve (user=arjun) = 50 on arjunShare.
+False <- arjun : reserve (*) = 50 on arjunShare.
diff --git a/tests/t24.dnp b/tests/t24.dnp
new file mode 100644
index 0000000..aa4da44
--- /dev/null
+++ b/tests/t24.dnp
@@ -0,0 +1,12 @@
+True <- root : NewShare net0 for (*) [reserve <= 200] on rootShare.
+// Original test case inspected the flows in rootshare. We use net0 instead
+// and try to exceed the limit on net0.
+True <- root : reserve(*) = 10 on net0 from 0 to 10.
+False <- root : reserve(*) = 191 on net0.
+True <- root : Tick 5.
+False <- root : reserve(*) = 191 on net0.
+True <- root : Tick 2.
+False <- root : reserve(*) = 191 on net0.
+True <- root : Tick 4.
+True <- root : reserve(*) = 200 on net0.
+
diff --git a/tests/t25.dnp b/tests/t25.dnp
new file mode 100644
index 0000000..5842b8b
--- /dev/null
+++ b/tests/t25.dnp
@@ -0,0 +1,16 @@
+True <- root : NewShare net0 for (*) [reserve <= 200] on rootShare.
+// Original test case inspected the flows in rootshare. We use net0 instead
+// and try to exceed the limit on net0.
+True <- root : reserve(*) = 10 on net0 from 5 to 10.
+True <- root : reserve(*) = 200 on net0 from now to +1.
+True <- root : Tick 4.
+True <- root : reserve(*) = 200 on net0 from now to +1.
+True <- root : Tick 1.
+False <- root : reserve(*) = 191 on net0 from now to +1.
+True <- root : Tick 4.
+False <- root : reserve(*) = 191 on net0 from now to +1.
+True <- root : Tick 1.
+True <- root : reserve(*) = 200 on net0 from now to +1.
+
+
+
diff --git a/tests/t3.dnp b/tests/t3.dnp
new file mode 100644
index 0000000..6dee327
--- /dev/null
+++ b/tests/t3.dnp
@@ -0,0 +1,2 @@
+True <- root : AddUser arjun.
+True <- root : AddUser adf.
diff --git a/tests/t4.dnp b/tests/t4.dnp
new file mode 100644
index 0000000..feeb94d
--- /dev/null
+++ b/tests/t4.dnp
@@ -0,0 +1,2 @@
+True <- root : AddUser arjun.
+False <- root : AddUser arjun.
diff --git a/tests/t5.dnp b/tests/t5.dnp
new file mode 100644
index 0000000..a0a4374
--- /dev/null
+++ b/tests/t5.dnp
@@ -0,0 +1,2 @@
+True <- root : AddUser arjun.
+True <- root : Grant rootShare to arjun.
diff --git a/tests/t6.dnp b/tests/t6.dnp
new file mode 100644
index 0000000..a17e72c
--- /dev/null
+++ b/tests/t6.dnp
@@ -0,0 +1,3 @@
+True <- root : AddUser arjun.
+True <- root : NewShare arjunShare for (*) [reserve<=100] on rootShare.
+True <- root : Grant arjunShare to arjun.
diff --git a/tests/t7.dnp b/tests/t7.dnp
new file mode 100644
index 0000000..9a25bb5
--- /dev/null
+++ b/tests/t7.dnp
@@ -0,0 +1,7 @@
+True <- root : AddUser arjun.
+True <- root : AddUser adf.
+True <- root : NewShare arjunShare for (*) [reserve<=100] on rootShare.
+True <- root : Grant arjunShare to arjun.
+False <- arjun : NewShare adfShare for (*) [reserve <= 200] on arjunShare.
+False <- arjun : Grant adfShare to adf.
+
diff --git a/tests/t8.dnp b/tests/t8.dnp
new file mode 100644
index 0000000..d7dd947
--- /dev/null
+++ b/tests/t8.dnp
@@ -0,0 +1,6 @@
+True <- root : AddUser arjun.
+True <- root : AddUser adf.
+True <- root : NewShare arjunShare for (*) [reserve<=100] on rootShare.
+True <- root : Grant arjunShare to arjun.
+True <- arjun : NewShare adfShare for (*) [reserve <= 50] on arjunShare.
+True <- arjun : Grant adfShare to adf.
diff --git a/tests/t9.dnp b/tests/t9.dnp
new file mode 100644
index 0000000..742421d
--- /dev/null
+++ b/tests/t9.dnp
@@ -0,0 +1,7 @@
+True <- root : AddUser arjun.
+True <- root : AddUser adf.
+True <- root : NewShare arjunShare for (*) [reserve<=100] on rootShare.
+True <- root : Grant arjunShare to arjun.
+True <- arjun : NewShare adfShare for (*) [reserve <= 50] on arjunShare.
+True <- arjun : Grant adfShare to adf.
+False <- arjun : Grant adfShare to nonUser.