Thanks @dani-i for your answer and improvement proposal!
I have included the before-method in all three testing files now.
market_order_test.js file amended and all 16 tests running successfully.
Code below:
Full code available at: https://github.com/sneicode/DEX
const Dex = artifacts.require("Dex")
const Link = artifacts.require("Link")
const truffleAssert = require("truffle-assertions")
contract("Dex", accounts => {
let dex
let link
before (async function(){
dex = await Dex.deployed()
link = await Link.deployed()
await dex.addToken(web3.utils.fromUtf8("LINK"), link.address)
})
// When creating a SELL market order, the seller needs to have sufficient tokens for the trade
it("should throw when creating a sell market order with a 0 token balance ", async () => {
let balance = await dex.balances(accounts[0], web3.utils.fromUtf8("LINK"))
assert.equal(balance.toNumber(), 0, "initial Link token balance is not 0")
await truffleAssert.reverts(
dex.createMarketOrder(1, web3.utils.fromUtf8("LINK"), 10)
)
})
// Market orders can be submitted even if the order book is empty
it("Market orders can be submitted even if the order book is empty", async () => {
await dex.depositEth({value: 50000})
let orderbook = await dex.getOrderBook(web3.utils.fromUtf8("LINK"), 0)
assert(orderbook.length == 0, "buy side orderbook length is not 0")
await truffleAssert.passes(
dex.createMarketOrder(0, web3.utils.fromUtf8("LINK"), 10)
)
})
// Market orders should be filled until the order book is 100% filled
it("Market orders should not fill more limit orders than the market order amount", async () => {
// get SELL side orderbook and assure it is empty at start of test
let orderbook = await dex.getOrderBook(web3.utils.fromUtf8("LINK"), 1)
assert(orderbook.length == 0, "SELL side order book is not empty at start of test")
// provide 3 accounts with LINK tokens from account 0
await link.transfer(accounts[1], 150)
await link.transfer(accounts[2], 150)
await link.transfer(accounts[3], 150)
// approve accounts 1-3 for DEX to sell 50 link tokens per account
await link.approve(dex.address, 50, {from: accounts[1]})
await link.approve(dex.address, 50, {from: accounts[2]})
await link.approve(dex.address, 50, {from: accounts[3]})
// deposit LINK tokens into Dex
await dex.deposit(50, web3.utils.fromUtf8("LINK"), {from: accounts[1]})
await dex.deposit(50, web3.utils.fromUtf8("LINK"), {from: accounts[2]})
await dex.deposit(50, web3.utils.fromUtf8("LINK"), {from: accounts[3]})
// create 3 SELL side limit orders, 1 each for accounts 1 - 3
await dex.createLimitOrder(1, web3.utils.fromUtf8("LINK"), 5, 300, {from: accounts[1]})
await dex.createLimitOrder(1, web3.utils.fromUtf8("LINK"), 5, 400, {from: accounts[2]})
await dex.createLimitOrder(1, web3.utils.fromUtf8("LINK"), 5, 500, {from: accounts[3]})
// create market order that fills 2/3 of the order book
await dex.createMarketOrder(0, web3.utils.fromUtf8("LINK"), 10)
// get SELL side of orderbook once again
orderbook = await dex.getOrderBook(web3.utils.fromUtf8("LINK"), 1)
// assure length is 1, (2 thirds consumed and 1 limitOrder left)
assert(orderbook.length == 1, "remaining SELL side orders is not 1")
assert(orderbook[0].filled == 0, "remaining SELL side order should be unfilled")
})
// Market orders should be filled until the order book is empty
it("Market orders should be filled until market order is empty", async () => {
// check if SELL order book has 1 entry remaining
let orderbook = await dex.getOrderBook(web3.utils.fromUtf8("LINK"), 1)
assert(orderbook.length == 1, "SELL side order book should have 1 order left")
// add 2 sell side limit orders to orderbook
await dex.createLimitOrder(1, web3.utils.fromUtf8("LINK"), 5, 400, {from: accounts[1]})
await dex.createLimitOrder(1, web3.utils.fromUtf8("LINK"), 5, 500, {from: accounts[2]})
// check buyer link balance before adding new market order
let beforeBalance = await dex.balances(accounts[0], web3.utils.fromUtf8("LINK"))
// create Market order that goes beyond available tokens (15 available, 35 missing)
await dex.createMarketOrder(0, web3.utils.fromUtf8("LINK"), 50)
// check buyer link balance after adding new market order
let updatedBalance = await dex.balances(accounts[0], web3.utils.fromUtf8("LINK"))
// buyer should have 15 link more even that marketorder was for 50 link
assert.equal(beforeBalance.toNumber() + 15, updatedBalance.toNumber())
})
// the eth balance of the buyer should decrease with the filled amount
it("the eth balance of the buyer should decrease with the filled ammount", async () => {
// seller deposit link and creates sell limit order for 1 Link
await link.approve(dex.address, 500, {from: accounts[1]})
await dex.createLimitOrder(1, web3.utils.fromUtf8("LINK"), 1, 300, {from: accounts[1]})
// check buyer eth balance before and after adding new market order
let beforeBalance = await dex.balances(accounts[0], web3.utils.fromUtf8("ETH"))
await dex.createMarketOrder(0, web3.utils.fromUtf8("LINK"), 1)
let updatedBalance = await dex.balances(accounts[0], web3.utils.fromUtf8("ETH"))
assert.equal(beforeBalance.toNumber() - 300, updatedBalance.toNumber())
})
// the token balances of the limit order sellers should decrease with the filled amount
it("the token balances of the limit order sellers should decrease with the filled amount", async () => {
let orderbook = await dex.getOrderBook(web3.utils.fromUtf8("LINK"), 1)
assert(orderbook.length == 0, "Sell side orderbook should be empty at start of test")
// seller account [2] deposit link
await link.approve(dex.address, 500, {from: accounts[2]})
await dex.deposit(50, web3.utils.fromUtf8("LINK"), {from: accounts[2]})
await dex.createLimitOrder(1, web3.utils.fromUtf8("LINK"), 1, 300, {from: accounts[1]})
await dex.createLimitOrder(1, web3.utils.fromUtf8("LINK"), 1, 400, {from: accounts[2]})
// check seller link balances before trade
let account1beforeBalance = await dex.balances(accounts[1], web3.utils.fromUtf8("LINK"))
let account2beforeBalance = await dex.balances(accounts[2], web3.utils.fromUtf8("LINK"))
// account[0] buys 2 available Link
await dex.createMarketOrder(0, web3.utils.fromUtf8("LINK"), 2)
let account1updatedBalance = await dex.balances(accounts[1], web3.utils.fromUtf8("LINK"))
let account2updatedBalance = await dex.balances(accounts[2], web3.utils.fromUtf8("LINK"))
assert.equal(account1beforeBalance.toNumber() - 1, account1updatedBalance.toNumber())
assert.equal(account2beforeBalance.toNumber() - 1, account2updatedBalance.toNumber())
})
// Filled limit orders should be removed from the orderbook
it("Filled limit orders should be removed from the orderbook", async () => {
// seller deposit link tokens and creates a limitorder for 1 link at 300 wei
await link.approve(dex.address, 500)
await dex.deposit(50, web3.utils.fromUtf8("LINK"))
await dex.depositEth({value: 10000})
let orderbook = await dex.getOrderBook(web3.utils.fromUtf8("LINK"), 1)
await dex.createLimitOrder(1, web3.utils.fromUtf8("LINK"), 1, 300)
await dex.createMarketOrder(0, web3.utils.fromUtf8("LINK"), 1)
orderbook = await dex.getOrderBook(web3.utils.fromUtf8("LINK"), 1)
assert(orderbook.length == 0, "sell side order book shoud be empty after trade")
})
// Partly filled limit orders should be modified to represent the filled/remaining amount
it("partially filled limit orders should be removed from the orderbook", async () => {
let orderbook = await dex.getOrderBook(web3.utils.fromUtf8("LINK"), 1)
assert(orderbook.length == 0, "Sell side orderbook should be empty at start of test")
await dex.createLimitOrder(1, web3.utils.fromUtf8("LINK"), 2, 300)
await dex.createMarketOrder(0, web3.utils.fromUtf8("LINK"), 1)
orderbook = await dex.getOrderBook(web3.utils.fromUtf8("LINK"), 1)
// amount - filled should be remaining order amount
assert.equal(orderbook[0].filled, 1)
assert.equal(orderbook[0].amount, 2)
})
})
It has taken me a while to sort errors in this testing file but I finally found them (some myself and others comparing to the solution) Some typos and missing “await” flags. -
Note on the side: error hints from the console are not very helpful !!).
Would also like to know more about the challenges to improving this DEX contract that Filip mentions in this video but without him providing further leads?
Could you suggest an example challenge for a “developing developer” ;O) how to improve the contract?
thank you again for your support!
yestome
