QSP-39 AreEth1DataEqual Should Return True If Both Nil (#6372)

* resolve small core issue

* add tests

Co-authored-by: prylabs-bulldozer[bot] <58059840+prylabs-bulldozer[bot]@users.noreply.github.com>

beacon-chain/core/blocks/block_operations.go

@@ -112,7 +112,11 @@ func ProcessEth1DataInBlock(beaconState *stateTrie.BeaconState, block *ethpb.Bea
 	return beaconState, nil
 }
 
-func areEth1DataEqual(a, b *ethpb.Eth1Data) bool {
+// AreEth1DataEqual checks equality between two eth1 data objects.
+func AreEth1DataEqual(a, b *ethpb.Eth1Data) bool {
+	if a == nil && b == nil {
+		return true
+	}
 	if a == nil || b == nil {
 		return false
 	}
@@ -130,7 +134,7 @@ func Eth1DataHasEnoughSupport(beaconState *stateTrie.BeaconState, data *ethpb.Et
 	data = stateTrie.CopyETH1Data(data)
 
 	for _, vote := range beaconState.Eth1DataVotes() {
-		if areEth1DataEqual(vote, data) {
+		if AreEth1DataEqual(vote, data) {
 			voteCount++
 		}
 	}

beacon-chain/core/blocks/block_operations_fuzz_test.go

@@ -90,8 +90,8 @@ func TestFuzzareEth1DataEqual_10000(t *testing.T) {
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(eth1data)
 		fuzzer.Fuzz(eth1data2)
-		areEth1DataEqual(eth1data, eth1data2)
+		AreEth1DataEqual(eth1data, eth1data2)
-		areEth1DataEqual(eth1data, eth1data)
+		AreEth1DataEqual(eth1data, eth1data)
 	}
 }
 

beacon-chain/core/blocks/block_operations_test.go

@@ -2224,3 +2224,75 @@ func TestVerifyAttestations_HandlesPlannedFork(t *testing.T) {
 		t.Fatal(err)
 	}
 }
+
+func TestAreEth1DataEqual(t *testing.T) {
+	type args struct {
+		a *ethpb.Eth1Data
+		b *ethpb.Eth1Data
+	}
+	tests := []struct {
+		name string
+		args args
+		want bool
+	}{
+		{
+			name: "true when both are nil",
+			args: args{
+				a: nil,
+				b: nil,
+			},
+			want: true,
+		},
+		{
+			name: "false when only one is nil",
+			args: args{
+				a: nil,
+				b: &ethpb.Eth1Data{
+					DepositRoot:  make([]byte, 32),
+					DepositCount: 0,
+					BlockHash:    make([]byte, 32),
+				},
+			},
+			want: false,
+		},
+		{
+			name: "true when real equality",
+			args: args{
+				a: &ethpb.Eth1Data{
+					DepositRoot:  make([]byte, 32),
+					DepositCount: 0,
+					BlockHash:    make([]byte, 32),
+				},
+				b: &ethpb.Eth1Data{
+					DepositRoot:  make([]byte, 32),
+					DepositCount: 0,
+					BlockHash:    make([]byte, 32),
+				},
+			},
+			want: true,
+		},
+		{
+			name: "false is field value differs",
+			args: args{
+				a: &ethpb.Eth1Data{
+					DepositRoot:  make([]byte, 32),
+					DepositCount: 0,
+					BlockHash:    make([]byte, 32),
+				},
+				b: &ethpb.Eth1Data{
+					DepositRoot:  make([]byte, 32),
+					DepositCount: 64,
+					BlockHash:    make([]byte, 32),
+				},
+			},
+			want: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := blocks.AreEth1DataEqual(tt.args.a, tt.args.b); got != tt.want {
+				t.Errorf("AreEth1DataEqual() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}