From c3fd0e7c64e07c6097ddaf4550bdfbd675ee6f51 Mon Sep 17 00:00:00 2001
From: Emmanuel T Odeke <emmanuel@orijtech.com>
Date: Thu, 13 Apr 2023 11:12:21 +0300
Subject: [PATCH] test(client): add a fuzz test for QueryBalance (#15763)

---
 client/fuzz_test.go                           | 60 +++++++++++++++++++
 client/grpc_query_test.go                     |  2 +
 .../fuzz/FuzzQueryBalance/4bf93f2225e526ac    |  2 +
 3 files changed, 64 insertions(+)
 create mode 100644 client/fuzz_test.go
 create mode 100644 client/testdata/fuzz/FuzzQueryBalance/4bf93f2225e526ac

diff --git a/client/fuzz_test.go b/client/fuzz_test.go
new file mode 100644
index 000000000000..a28a0b4d9c3a
--- /dev/null
+++ b/client/fuzz_test.go
@@ -0,0 +1,60 @@
+package client_test
+
+import (
+	"context"
+	"testing"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/metadata"
+
+	"github.com/cosmos/cosmos-sdk/testutil/testdata"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/x/bank/types"
+)
+
+type fuzzSuite struct {
+	IntegrationTestSuite
+}
+
+func (fz *fuzzSuite) FuzzQueryBalance(f *testing.F) {
+	if testing.Short() {
+		f.Skip("In -short mode")
+	}
+
+	// gRPC query to test service should work
+	testRes, err := fz.testClient.Echo(context.Background(), &testdata.EchoRequest{Message: "hello"})
+	fz.Require().NoError(err)
+	fz.Require().Equal("hello", testRes.Message)
+
+	// 1. Generate some seeds.
+	bz, err := fz.cdc.Marshal(&types.QueryBalanceRequest{
+		Address: fz.genesisAccount.GetAddress().String(),
+		Denom:   sdk.DefaultBondDenom,
+	})
+	fz.Require().NoError(err)
+	f.Add(bz)
+
+	// 2. Now fuzz it and ensure that we don't get any panics.
+	ctx := context.Background()
+	f.Fuzz(func(t *testing.T, in []byte) {
+		qbReq := new(types.QueryBalanceRequest)
+		if err := fz.cdc.Unmarshal(in, qbReq); err != nil {
+			return
+		}
+
+		// gRPC query to bank service should work
+		var header metadata.MD
+		_, _ = fz.bankClient.Balance(
+			ctx,
+			qbReq,
+			grpc.Header(&header),
+		)
+	})
+}
+
+func FuzzQueryBalance(f *testing.F) {
+	fzs := new(fuzzSuite)
+	fzs.SetT(new(testing.T))
+	fzs.SetupSuite()
+	fzs.FuzzQueryBalance(f)
+}
diff --git a/client/grpc_query_test.go b/client/grpc_query_test.go
index f0594fc228f4..fd43d6cf812c 100644
--- a/client/grpc_query_test.go
+++ b/client/grpc_query_test.go
@@ -33,6 +33,7 @@ type IntegrationTestSuite struct {
 	suite.Suite
 
 	ctx                   sdk.Context
+	cdc                   codec.Codec
 	genesisAccount        *authtypes.BaseAccount
 	bankClient            types.QueryClient
 	testClient            testdata.QueryClient
@@ -96,6 +97,7 @@ func (s *IntegrationTestSuite) SetupSuite() {
 	// end of app init
 
 	s.ctx = app.BaseApp.NewContext(false, cmtproto.Header{})
+	s.cdc = cdc
 	queryHelper := baseapp.NewQueryServerTestHelper(s.ctx, interfaceRegistry)
 	types.RegisterQueryServer(queryHelper, bankKeeper)
 	testdata.RegisterQueryServer(queryHelper, testdata.QueryImpl{})
diff --git a/client/testdata/fuzz/FuzzQueryBalance/4bf93f2225e526ac b/client/testdata/fuzz/FuzzQueryBalance/4bf93f2225e526ac
new file mode 100644
index 000000000000..73d7776fdb93
--- /dev/null
+++ b/client/testdata/fuzz/FuzzQueryBalance/4bf93f2225e526ac
@@ -0,0 +1,2 @@
+go test fuzz v1
+[]byte("\n-cosmos1wrq8cagsama0xwf2vmlzgrkyynfsxuyhturvyz\x12\x0500000")