From 2f66d1a46ce7ca5830993ca7b51230f23e3a0356 Mon Sep 17 00:00:00 2001
From: Preston Van Loon <preston@prysmaticlabs.com>
Date: Wed, 5 May 2021 15:18:55 -0500
Subject: [PATCH] Use mock web3/powchain for fuzz test (#8866)

* Use mock web3/powchain for fuzz test

* gofmt

* build viz
---
 beacon-chain/powchain/testing/BUILD.bazel | 5 ++++-
 fuzz/BUILD.bazel                          | 1 +
 fuzz/block_fuzz.go                        | 3 ++-
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/beacon-chain/powchain/testing/BUILD.bazel b/beacon-chain/powchain/testing/BUILD.bazel
index c5a684737a76..6850eb40f6fb 100644
--- a/beacon-chain/powchain/testing/BUILD.bazel
+++ b/beacon-chain/powchain/testing/BUILD.bazel
@@ -8,7 +8,10 @@ go_library(
         "mock_powchain.go",
     ],
     importpath = "github.com/prysmaticlabs/prysm/beacon-chain/powchain/testing",
-    visibility = ["//beacon-chain:__subpackages__"],
+    visibility = [
+        "//beacon-chain:__subpackages__",
+        "//fuzz:__pkg__",
+    ],
     deps = [
         "//beacon-chain/powchain/types:go_default_library",
         "//beacon-chain/state/interface:go_default_library",
diff --git a/fuzz/BUILD.bazel b/fuzz/BUILD.bazel
index 157b65618e4c..8cbe6f7e7579 100644
--- a/fuzz/BUILD.bazel
+++ b/fuzz/BUILD.bazel
@@ -75,6 +75,7 @@ go_fuzz_test(
         "//beacon-chain/blockchain:go_default_library",
         "//beacon-chain/operations/slashings:go_default_library",
         "//beacon-chain/forkchoice/protoarray:go_default_library",
+        "//beacon-chain/powchain/testing:go_default_library",
         "//shared/testutil:go_default_library",
         "@com_github_libp2p_go_libp2p_core//peer:go_default_library",
         "@com_github_libp2p_go_libp2p_pubsub//:go_default_library",
diff --git a/fuzz/block_fuzz.go b/fuzz/block_fuzz.go
index ddfddc6aab52..8ec37fabed39 100644
--- a/fuzz/block_fuzz.go
+++ b/fuzz/block_fuzz.go
@@ -24,6 +24,7 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/operations/voluntaryexits"
 	"github.com/prysmaticlabs/prysm/beacon-chain/p2p"
 	p2pt "github.com/prysmaticlabs/prysm/beacon-chain/p2p/testing"
+	powt "github.com/prysmaticlabs/prysm/beacon-chain/powchain/testing"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateV0"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
 	"github.com/prysmaticlabs/prysm/beacon-chain/sync"
@@ -133,7 +134,7 @@ func BeaconFuzzBlock(b []byte) {
 	}
 
 	chain, err := blockchain.NewService(context.Background(), &blockchain.Config{
-		ChainStartFetcher: nil,
+		ChainStartFetcher: powt.NewPOWChain(),
 		BeaconDB:          db1,
 		DepositCache:      nil,
 		AttPool:           ap,