fix after review, added extra check

process/errors.go

@@ -109,3 +109,6 @@ var ErrEmptyAppVersionString = errors.New("empty app version string")
 
 // ErrEmptyCommitString signals than an empty commit id string has been provided
 var ErrEmptyCommitString = errors.New("empty commit id string")
+
+// ErrEmptyPubKey signals that an empty public key has been provided
+var ErrEmptyPubKey = errors.New("public key is empty")

process/nodeGroupProcessor.go

@@ -244,6 +244,10 @@ func (ngp *NodeGroupProcessor) handleHeartbeatCacheUpdate() {
 
 // GetWaitingEpochsLeftForPublicKey returns the number of epochs left for the public key until it becomes eligible
 func (ngp *NodeGroupProcessor) GetWaitingEpochsLeftForPublicKey(publicKey string) (*data.WaitingEpochsLeftApiResponse, error) {
+	if len(publicKey) == 0 {
+		return nil, ErrEmptyPubKey
+	}
+
 	observers, err := ngp.proc.GetAllObservers()
 	if err != nil {
 		return nil, err

process/nodeGroupProcessor_test.go

@@ -637,6 +637,19 @@ func TestNodeGroupProcessor_GetWaitingEpochsLeftForPublicKey(t *testing.T) {
 	t.Parallel()
 
 	expectedErr := errors.New("expected error")
+	t.Run("empty pub key should error", func(t *testing.T) {
+		t.Parallel()
+
+		proc, _ := process.NewNodeGroupProcessor(
+			&mock.ProcessorStub{},
+			&mock.HeartbeatCacherMock{},
+			10,
+		)
+
+		response, err := proc.GetWaitingEpochsLeftForPublicKey("")
+		require.Nil(t, response)
+		require.Equal(t, process.ErrEmptyPubKey, err)
+	})
 	t.Run("GetAllObservers returns error should error", func(t *testing.T) {
 		t.Parallel()
 
@@ -650,7 +663,7 @@ func TestNodeGroupProcessor_GetWaitingEpochsLeftForPublicKey(t *testing.T) {
 			10,
 		)
 
-		response, err := proc.GetWaitingEpochsLeftForPublicKey("")
+		response, err := proc.GetWaitingEpochsLeftForPublicKey("key")
 		require.Nil(t, response)
 		require.Equal(t, expectedErr, err)
 	})
@@ -673,7 +686,7 @@ func TestNodeGroupProcessor_GetWaitingEpochsLeftForPublicKey(t *testing.T) {
 			10,
 		)
 
-		response, err := proc.GetWaitingEpochsLeftForPublicKey("")
+		response, err := proc.GetWaitingEpochsLeftForPublicKey("key")
 		require.Nil(t, response)
 		require.Equal(t, process.ErrSendingRequest, err)
 	})