diff --git a/core/chain_manager_test.go b/core/chain_manager_test.go
index a88afd7c8..8d1b7865d 100644
--- a/core/chain_manager_test.go
+++ b/core/chain_manager_test.go
@@ -44,7 +44,7 @@ func testFork(t *testing.T, bman *BlockProcessor, i, N int, f func(td1, td2 *big
 	// extend the fork
 	parent := bman2.bc.CurrentBlock()
 	chainB := makeChain(bman2, parent, N, db, ForkSeed)
-	err = bman2.bc.InsertChain(chainB)
+	_, err = bman2.bc.InsertChain(chainB)
 	if err != nil {
 		t.Fatal("Insert chain error for fork:", err)
 	}
@@ -108,7 +108,7 @@ func loadChain(fn string, t *testing.T) (types.Blocks, error) {
 }
 
 func insertChain(done chan bool, chainMan *ChainManager, chain types.Blocks, t *testing.T) {
-	err := chainMan.InsertChain(chain)
+	_, err := chainMan.InsertChain(chain)
 	if err != nil {
 		fmt.Println(err)
 		t.FailNow()
diff --git a/eth/downloader/downloader_test.go b/eth/downloader/downloader_test.go
index 8843ca0c7..5518163ca 100644
--- a/eth/downloader/downloader_test.go
+++ b/eth/downloader/downloader_test.go
@@ -62,10 +62,10 @@ func (dl *downloadTester) hasBlock(hash common.Hash) bool {
 	return false
 }
 
-func (dl *downloadTester) insertChain(blocks types.Blocks) error {
+func (dl *downloadTester) insertChain(blocks types.Blocks) (int, error) {
 	dl.insertedBlocks += len(blocks)
 
-	return nil
+	return 0, nil
 }
 
 func (dl *downloadTester) getHashes(hash common.Hash) error {