diff --git a/statediff/indexer/database/file/statediffing_test/eth.header_cids.csv b/statediff/indexer/database/file/statediffing_test/eth.header_cids.csv
new file mode 100644
index 000000000..e69de29bb
diff --git a/statediff/indexer/database/file/statediffing_test/eth.log_cids.csv b/statediff/indexer/database/file/statediffing_test/eth.log_cids.csv
new file mode 100644
index 000000000..e69de29bb
diff --git a/statediff/indexer/database/file/statediffing_test/eth.receipt_cids.csv b/statediff/indexer/database/file/statediffing_test/eth.receipt_cids.csv
new file mode 100644
index 000000000..e69de29bb
diff --git a/statediff/indexer/database/file/statediffing_test/eth.state_cids.csv b/statediff/indexer/database/file/statediffing_test/eth.state_cids.csv
new file mode 100644
index 000000000..e69de29bb
diff --git a/statediff/indexer/database/file/statediffing_test/eth.storage_cids.csv b/statediff/indexer/database/file/statediffing_test/eth.storage_cids.csv
new file mode 100644
index 000000000..e69de29bb
diff --git a/statediff/indexer/database/file/statediffing_test/eth.transaction_cids.csv b/statediff/indexer/database/file/statediffing_test/eth.transaction_cids.csv
new file mode 100644
index 000000000..e69de29bb
diff --git a/statediff/indexer/database/file/statediffing_test/eth.uncle_cids.csv b/statediff/indexer/database/file/statediffing_test/eth.uncle_cids.csv
new file mode 100644
index 000000000..e69de29bb
diff --git a/statediff/indexer/database/file/statediffing_test/ipld.blocks.csv b/statediff/indexer/database/file/statediffing_test/ipld.blocks.csv
new file mode 100644
index 000000000..e69de29bb
diff --git a/statediff/indexer/database/file/statediffing_test/public.nodes.csv b/statediff/indexer/database/file/statediffing_test/public.nodes.csv
new file mode 100644
index 000000000..e69de29bb
diff --git a/statediff/test_helpers/mocks/backend.go b/statediff/test_helpers/mocks/backend.go
index 3041425ed..92580bcf6 100644
--- a/statediff/test_helpers/mocks/backend.go
+++ b/statediff/test_helpers/mocks/backend.go
@@ -21,6 +21,8 @@ import (
 	"math/big"
 	"time"
 
+	"github.com/ethereum/go-ethereum/internal/ethapi"
+
 	"github.com/ethereum/go-ethereum"
 	"github.com/ethereum/go-ethereum/accounts"
 	"github.com/ethereum/go-ethereum/common"
@@ -36,6 +38,8 @@ import (
 	"github.com/ethereum/go-ethereum/rpc"
 )
 
+var _ ethapi.Backend = &Backend{}
+
 // Builder is a mock state diff builder
 type Backend struct {
 	StartingBlock       uint64
@@ -81,8 +85,8 @@ func (backend *Backend) SuggestGasTipCap(ctx context.Context) (*big.Int, error)
 	panic("not implemented") // TODO: Implement
 }
 
-func (backend *Backend) FeeHistory(ctx context.Context, blockCount int, lastBlock rpc.BlockNumber, rewardPercentiles []float64) (*big.Int, [][]*big.Int, []*big.Int, []float64, error) {
-	panic("not implemented") // TODO: Implement
+func (backend *Backend) FeeHistory(ctx context.Context, blockCount uint64, lastBlock rpc.BlockNumber, rewardPercentiles []float64) (*big.Int, [][]*big.Int, []*big.Int, []float64, error) {
+	panic("implement me")
 }
 
 func (backend *Backend) ChainDb() ethdb.Database {