diff --git a/app/encoding.go b/app/encoding.go
index e87ec971..766295be 100644
--- a/app/encoding.go
+++ b/app/encoding.go
@@ -28,6 +28,7 @@ func TmpAppOptions() simsutils.AppOptionsMap {
 	return appOpts
 }
 
+// NewTmpBabylonApp returns a new BabylonApp
 func NewTmpBabylonApp() *BabylonApp {
 	tbs, _ := signer.SetupTestBlsSigner()
 	blsSigner := checkpointingtypes.BlsSigner(tbs)
diff --git a/app/signer/private.go b/app/signer/private.go
index b6d95040..9c91e6d4 100644
--- a/app/signer/private.go
+++ b/app/signer/private.go
@@ -12,6 +12,7 @@ import (
 	checkpointingtypes "github.com/babylonlabs-io/babylon/x/checkpointing/types"
 )
 
+// ConsensusKey represents the consensus keys
 type ConsensusKey struct {
 	Comet *cmtprivval.FilePVKey
 	Bls   *privval.BlsPVKey
diff --git a/x/checkpointing/types/errors.go b/x/checkpointing/types/errors.go
index f212924c..2971bd5c 100644
--- a/x/checkpointing/types/errors.go
+++ b/x/checkpointing/types/errors.go
@@ -19,4 +19,5 @@ var (
 	ErrConflictingCheckpoint   = errorsmod.Register(ModuleName, 1213, "Conflicting checkpoint is found")
 	ErrInvalidAppHash          = errorsmod.Register(ModuleName, 1214, "Provided app hash is Invalid")
 	ErrInsufficientVotingPower = errorsmod.Register(ModuleName, 1215, "Accumulated voting power is not greater than 2/3 of total power")
+	ErrValAddrDoesNotExist     = errorsmod.Register(ModuleName, 1216, "Validator address does not exist")
 )
diff --git a/x/checkpointing/vote_ext_test.go b/x/checkpointing/vote_ext_test.go
index 0a4dcc9d..a0001b89 100644
--- a/x/checkpointing/vote_ext_test.go
+++ b/x/checkpointing/vote_ext_test.go
@@ -175,40 +175,3 @@ func FuzzExtendVote_InvalidBlockHash(f *testing.F) {
 		require.NoError(t, err)
 	})
 }
-
-// FuzzExtendVote_EmptyBLSPrivKey tests the case where the
-// BLS private key of the private signer is missing
-func FuzzExtendVote_EmptyBLSPrivKey(f *testing.F) {
-	datagen.AddRandomSeedsToFuzzer(f, 10)
-
-	f.Fuzz(func(t *testing.T, seed int64) {
-		r := rand.New(rand.NewSource(seed))
-		// generate the validator set with 10 validators as genesis
-		genesisValSet, ps, err := datagen.GenesisValidatorSetWithPrivSigner(10)
-		require.NoError(t, err)
-
-		// set the BLS private key to be nil to trigger panic
-		ps.PV.Bls.PrivKey = nil
-		helper := testhelper.NewHelperWithValSet(t, genesisValSet, ps)
-		ek := helper.App.EpochingKeeper
-
-		epoch := ek.GetEpoch(helper.Ctx)
-		require.Equal(t, uint64(1), epoch.EpochNumber)
-
-		// go to block 10, reaching epoch boundary
-		interval := ek.GetParams(helper.Ctx).EpochInterval
-		for i := uint64(0); i < interval-2; i++ {
-			_, err := helper.ApplyEmptyBlockWithVoteExtension(r)
-			require.NoError(t, err)
-		}
-
-		req := &abci.RequestExtendVote{
-			Hash:   datagen.GenRandomByteArray(r, types.HashSize),
-			Height: 10,
-		}
-
-		// error is expected due to nil BLS private key
-		_, err = helper.App.ExtendVote(helper.Ctx, req)
-		require.Error(t, err)
-	})
-}