I am trying to run a test with truffle.

But I am getting an error:

Error: Invalid number of arguments to Solidity function

My contract looks like this:

pragma solidity ^0.4.0;

contract Leontest1 {
    uint flight_number;
    uint day_number;
    string low_no = "This is a low flight number";

    function Leontest1() {

    function low_numbers (uint flight_number) returns (string) {
        if (flight_number > 6) {low_no = "This is not a low flight number";} else {low_no = low_no;}
        return low_no;


And my test.js looks like this:

var Leontest1 = artifacts.require("./Leontest1.sol");

contract('Leontest1:low_numbers', function(accounts) {
  it("should assert true", async function() {
    const contract = await Leontest1.deployed();
    await contract.low_numbers(5);
    const result = await contract.low_numbers.call();
    assert.equal(result,"This is a low flight number");


Can someone help me please?

I am using Truffle v4.1.7

Thanks in advance,

  • What's this doing in your code? {low_no = low_no;} May 16, 2018 at 19:22

1 Answer 1


Well, function low_numbers takes an argument, which you are not passing it.

Solidity code:

function low_numbers (uint flight_number) returns (string) {

Javascript code:

const result = await contract.low_numbers.call();

BTW, you are calling it twice (what exactly is the point in that???):

await contract.low_numbers(5);
const result = await contract.low_numbers.call();
  • I have taken out the line const result = await contract.low_numbers.call();
    – Victor
    Jun 3, 2018 at 2:05

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