add more tests

rpcx/mock/depositserver.go

@@ -0,0 +1,19 @@
+package mock
+
+import (
+	"context"
+
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+type DepositServer struct {
+}
+
+func (*DepositServer) Deposit(ctx context.Context, req *DepositRequest) (*DepositResponse, error) {
+	if req.GetAmount() < 0 {
+		return nil, status.Errorf(codes.InvalidArgument, "cannot deposit %v", req.GetAmount())
+	}
+
+	return &DepositResponse{Ok: true}, nil
+}