testing(json rpc): Add backend test suite with mock grpc query client

go.mod

@@ -133,6 +133,7 @@ require (
 	github.com/spf13/afero v1.8.2 // indirect
 	github.com/spf13/jwalterweatherman v1.1.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
+	github.com/stretchr/objx v0.4.0 // indirect
 	github.com/subosito/gotenv v1.3.0 // indirect
 	github.com/syndtr/goleveldb v1.0.1-0.20210819022825-2ae1ddf74ef7 // indirect
 	github.com/tendermint/btcd v0.1.1 // indirect

rpc/backend/backend_suite_test.go

@@ -0,0 +1,73 @@
+package backend
+
+import (
+	"testing"
+
+	"github.com/cosmos/cosmos-sdk/client"
+	"github.com/cosmos/cosmos-sdk/server"
+	grpctypes "github.com/cosmos/cosmos-sdk/types/grpc"
+	mock "github.com/stretchr/testify/mock"
+	"github.com/stretchr/testify/require"
+	"github.com/stretchr/testify/suite"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/metadata"
+
+	"github.com/evmos/ethermint/rpc/backend/mocks"
+	rpc "github.com/evmos/ethermint/rpc/types"
+	evmtypes "github.com/evmos/ethermint/x/evm/types"
+)
+
+type BackendTestSuite struct {
+	suite.Suite
+	backend *Backend
+}
+
+func TestBackendTestSuite(t *testing.T) {
+	suite.Run(t, new(BackendTestSuite))
+}
+
+// SetupTest is executed before every BackendTestSuite test
+func (suite *BackendTestSuite) SetupTest() {
+	ctx := server.NewDefaultContext()
+	ctx.Viper.Set("telemetry.global-labels", []interface{}{})
+	clientCtx := client.Context{}.WithChainID("ethermint_9000-1").WithHeight(1)
+	allowUnprotectedTxs := false
+
+	suite.backend = NewBackend(ctx, ctx.Logger, clientCtx, allowUnprotectedTxs)
+
+	queryClient := mocks.NewQueryClient(suite.T())
+	var header metadata.MD
+	RegisterMockQueries(queryClient, &header)
+
+	suite.backend.queryClient.QueryClient = queryClient
+	suite.backend.ctx = rpc.ContextWithHeight(1)
+}
+
+// QueryClient defines a mocked object that implements the grpc QueryCLient
+// interface. It's used on tests to test the JSON-RPC without running a grpc
+// client server. E.g. JSON-PRC-CLIENT -> BACKEND -> Mock GRPC CLIENT -> APP
+var _ evmtypes.QueryClient = &mocks.QueryClient{}
+
+// RegisterMockQueries registers the queries and their respective responses,
+// so that they can be called in tests using the queryClient
+func RegisterMockQueries(queryClient *mocks.QueryClient, header *metadata.MD) {
+	queryClient.On("Params", rpc.ContextWithHeight(1), &evmtypes.QueryParamsRequest{}, grpc.Header(header)).
+		Return(&evmtypes.QueryParamsResponse{}, nil).
+		Run(func(args mock.Arguments) {
+			// If Params call is successful, also update the header height
+			arg := args.Get(2).(grpc.HeaderCallOption)
+			h := metadata.MD{}
+			h.Set(grpctypes.GRPCBlockHeightHeader, "1")
+			*arg.HeaderAddr = h
+		})
+}
+
+func TestQueryClient(t *testing.T) {
+	queryClient := mocks.NewQueryClient(t)
+	var header metadata.MD
+	RegisterMockQueries(queryClient, &header)
+
+	// mock calls for abstraction
+	_, err := queryClient.Params(rpc.ContextWithHeight(1), &evmtypes.QueryParamsRequest{}, grpc.Header(&header))
+	require.NoError(t, err)
+}

rpc/backend/evm_backend_test.go

@@ -0,0 +1,30 @@
+package backend
+
+import "github.com/ethereum/go-ethereum/common/hexutil"
+
+func (suite *BackendTestSuite) TestBlockNumber() {
+	testCases := []struct {
+		mame           string
+		malleate       func()
+		expBlockNumber hexutil.Uint64
+		expPass        bool
+	}{
+		{
+			"pass",
+			func() {
+			},
+			0x1,
+			true,
+		},
+	}
+	for _, tc := range testCases {
+		blockNumber, err := suite.backend.BlockNumber()
+
+		if tc.expPass {
+			suite.Require().NoError(err)
+			suite.Require().Equal(tc.expBlockNumber, blockNumber)
+		} else {
+			suite.Require().Error(err)
+		}
+	}
+}