Small refactoring and added UTs ro RPC (#48)

rpc/client.go

@@ -17,31 +17,11 @@ func JSONRPCCall(url, method string, params ...interface{}) (Response, error) {
 // the provided method and parameters, which is compatible with the Ethereum
 // JSON RPC Server.
 func JSONRPCCallWithContext(ctx context.Context, url, method string, parameters ...interface{}) (Response, error) {
-	params, err := json.Marshal(parameters)
+	httpReq, err := BuildJsonHTTPRequest(ctx, url, method, parameters...)
 	if err != nil {
 		return Response{}, err
 	}
 
-	req := Request{
-		JSONRPC: "2.0",
-		ID:      float64(1),
-		Method:  method,
-		Params:  params,
-	}
-
-	reqBody, err := json.Marshal(req)
-	if err != nil {
-		return Response{}, err
-	}
-
-	reqBodyReader := bytes.NewReader(reqBody)
-	httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, url, reqBodyReader)
-	if err != nil {
-		return Response{}, err
-	}
-
-	httpReq.Header.Add("Content-type", "application/json")
-
 	httpRes, err := http.DefaultClient.Do(httpReq)
 	if err != nil {
 		return Response{}, err

rpc/client_test.go

@@ -0,0 +1,66 @@
+package rpc
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func Test_JSONRPCCallWithContext(t *testing.T) {
+	tests := []struct {
+		name       string
+		result     string
+		resp       Response
+		statusCode int
+		err        error
+	}{
+		{
+			name:   "successfully executed request",
+			result: `{"result":"test"}`,
+			resp: Response{
+				Result: json.RawMessage(`"test"`),
+			},
+		},
+		{
+			name:       "unsuccessful status code returned by server",
+			statusCode: http.StatusUnauthorized,
+			err:        errors.New("invalid status code, expected: 200, found: 401"),
+		},
+	}
+	for _, tt := range tests {
+		tt := tt
+
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			svr := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				var res Request
+				require.NoError(t, json.NewDecoder(r.Body).Decode(&res))
+				require.Equal(t, "test", res.Method)
+
+				if tt.statusCode > 0 {
+					w.WriteHeader(tt.statusCode)
+				}
+
+				_, err := fmt.Fprint(w, tt.result)
+				require.NoError(t, err)
+			}))
+			defer svr.Close()
+
+			got, err := JSONRPCCallWithContext(context.Background(), svr.URL, "test")
+			if tt.err != nil {
+				require.Error(t, err)
+				require.EqualError(t, tt.err, err.Error())
+			} else {
+				require.NoError(t, err)
+				require.Equal(t, tt.resp, got)
+			}
+		})
+	}
+}

rpc/dbtxmanager.go

@@ -15,6 +15,7 @@ type DBTxScopedFn func(ctx context.Context, dbTx db.Tx) (interface{}, Error)
 // NewDbTxScope function to initiate DB scopped txs
 func (f *DBTxManager) NewDbTxScope(db db.DB, scopedFn DBTxScopedFn) (interface{}, Error) {
 	ctx := context.Background()
+
 	dbTx, err := db.BeginStateTransaction(ctx)
 	if err != nil {
 		return RPCErrorResponse(DefaultErrorCode, "failed to connect to the state", err)