diff --git a/test/FediChordSpec.hs b/test/FediChordSpec.hs
index 36ae2de..b6f08ad 100644
--- a/test/FediChordSpec.hs
+++ b/test/FediChordSpec.hs
@@ -5,7 +5,7 @@ import           Control.Exception
 import           Data.ASN1.Parse       (runParseASN1)
 import qualified Data.ByteString       as BS
 import qualified Data.Map.Strict       as Map
-import           Data.Maybe            (fromJust)
+import           Data.Maybe            (fromJust, isJust)
 import qualified Data.Set              as Set
 import           Data.Time.Clock.POSIX
 import           Network.Socket
@@ -212,6 +212,12 @@ spec = do
             responseWith a pa = responseTemplate {action = a, payload = Just pa}
 
             encodeDecodeAndCheck msg = runParseASN1 parseMessage (encodeMessage msg) `shouldBe` pure msg
+            largeMessage = responseWith Join $ JoinResponsePayload {
+                joinSuccessors = fromInteger <$> [-20..150]
+              , joinPredecessors = fromInteger <$> [5..11]
+              , joinCache = [ RemoteCacheEntry (exampleNodeState {nid = node}) 290001 | node <- [50602,506011..60000]]
+                                                                       }
+
         it "messages are encoded and decoded correctly from and to ASN1" $ do
             encodeDecodeAndCheck $ requestWith QueryID qidReqPayload
             encodeDecodeAndCheck $ requestWith Join jReqPayload
@@ -227,14 +233,14 @@ spec = do
         it "messages are encoded and decoded to ASN.1 DER properly" $
             deserialiseMessage (fromJust $ Map.lookup 1 (serialiseMessage 652  $ responseWith Ping pingResPayload)) `shouldBe` Right (responseWith Ping pingResPayload)
         it "messages too large for a single packet can (often) be split into multiple parts" $ do
-            let largeMessage = responseWith Join $ JoinResponsePayload {
-                joinSuccessors = fromInteger <$> [-20..150]
-              , joinPredecessors = fromInteger <$> [5..11]
-              , joinCache = [ RemoteCacheEntry (exampleNodeState {nid = node}) 290001 | node <- [50602,506011..60000]]
-                                                                       }
             -- TODO: once splitting works more efficient, test for exact number or payload, see #18
             length (serialiseMessage 600 largeMessage) > 1 `shouldBe` True
             length (serialiseMessage 6000 largeMessage) `shouldBe` 1
+        it "message part numbering starts at the submitted part number" $ do
+            isJust (Map.lookup 1 (serialiseMessage 600 largeMessage)) `shouldBe` True
+            let startAt5 = serialiseMessage 600 (largeMessage {part = 5})
+            Map.lookup 1 startAt5 `shouldBe` Nothing
+            part <$> (deserialiseMessage . fromJust) (Map.lookup 5 startAt5) `shouldBe` Right 5
 
 
 -- some example data