AutistMask/tests/sendMax.test.js

// The Send screen's "Max" control
// (https://git.eeqj.de/sneak/AutistMask/issues/198).
//
// For ETH it fills in the exact balance minus the fee reserve the
// confirmation screen's balance check gates on, never the four-decimal balance
// the Send screen shows; the confirmation screen re-derives that amount from
// its own estimate, and signs with that estimate's fee fields. For a token it
// fills in the whole balance, and the check that ETH covers the fee still
// applies.
//
// Driven through the real refreshBalances(), Send screen and confirmation
// screen, Sign & Send included, with only the node, the explorer and the DOM
// stubbed.

"use strict";

// What the stub node answers, and the signed transactions it was handed.
const mockNode = {
    balanceWei: 0n,
    feeData: null,
    broadcast: [],
};

// The token rows the stub explorer reports for the address.
const mockExplorer = { items: [] };

jest.mock("ethers", () => {
    const actual = jest.requireActual("ethers");
    class StubProvider {
        async getBalance() {
            return mockNode.balanceWei;
        }
        async lookupAddress() {
            return null;
        }
        async getFeeData() {
            return mockNode.feeData;
        }
        async estimateGas() {
            return 21000n;
        }
        async getCode() {
            return "0x";
        }
        async getTransactionCount() {
            return 1;
        }
        async getNetwork() {
            return { chainId: 1n };
        }
        async broadcastTransaction(signed) {
            mockNode.broadcast.push(signed);
            return { hash: "0x" + "ab".repeat(32) };
        }
    }
    return {
        ...actual,
        JsonRpcProvider: StubProvider,
        Network: { from: () => ({}) },
    };
});

jest.mock("../src/shared/log", () => ({
    log: {
        debugf: () => {},
        infof: () => {},
        warnf: () => {},
        errorf: () => {},
    },
    // The explorer's token list, which refreshBalances() also fetches.
    debugFetch: jest.fn(async () => ({
        ok: true,
        status: 200,
        json: async () => mockExplorer.items,
    })),
    urlOrigin: () => "",
    setRuntimeDebug: () => {},
    isDebug: () => false,
}));

// The wait screen polls for a receipt; these tests stop at the broadcast.
jest.mock("../src/popup/views/txStatus", () => ({
    showWait: jest.fn(),
    showError: jest.fn(),
}));

// The confirmation screen's Etherscan label lookup is the only fetch() these
// screens make; it fails, as it does offline.
global.fetch = jest.fn(() => {
    throw new Error("tests must not perform network requests");
});

const { makeStorageStub } = require("./support/storageStub");
global.chrome = { storage: makeStorageStub(), runtime: { sendMessage() {} } };

// A stub DOM: every id resolves to a recording element.
const elements = new Map();

function makeEl(id) {
    const handlers = new Map();
    return {
        id,
        textContent: "",
        innerHTML: "",
        value: "",
        disabled: false,
        style: {},
        dataset: {},
        classList: {
            add() {},
            remove() {},
            toggle() {},
            contains: () => false,
        },
        handlers,
        children: [],
        addEventListener(name, fn) {
            handlers.set(name, fn);
        },
        appendChild(child) {
            this.children.push(child);
            return child;
        },
        querySelectorAll: () => [],
        querySelector: () => null,
        remove() {},
        focus() {},
    };
}

global.document = {
    getElementById(id) {
        if (!elements.has(id)) elements.set(id, makeEl(id));
        return elements.get(id);
    },
    createElement: (tag) => makeEl(tag),
    body: { prepend() {}, appendChild() {} },
    addEventListener() {},
};
global.navigator = { clipboard: { writeText() {} } };

const { Transaction, Wallet, formatEther } = require("ethers");
const { refreshBalances } = require("../src/shared/balances");
const { encryptWithPassword } = require("../src/shared/vault");
const { state } = require("../src/shared/state");
const send = require("../src/popup/views/send");
const confirmTx = require("../src/popup/views/confirmTx");

const PRIVATE_KEY = "0x" + "11".repeat(32);
const HOLDER = new Wallet(PRIVATE_KEY).address;
const RECIPIENT = "0xC0FfEE0000000000000000000000000000c0fFEe";
const PASSWORD = "correct horse battery staple";

const GWEI = 1000000000n;
const GAS = 21000n;

// The Send screen shows this balance as 1.2345 ETH.
const BALANCE_WEI = 1234567890123456789n;

// A token the bundled list does not know, with enough holders to be listed.
const TOKEN = "0x" + "d".repeat(40);

// Fee data whose reserve is 21000 gas at `maxFeePerGas`. The expected cost,
// at gasPrice, is lower, as it is on mainnet.
function fees(maxFeePerGas) {
    return {
        maxFeePerGas,
        maxPriorityFeePerGas: GWEI,
        gasPrice: maxFeePerGas / 2n,
    };
}

// The balance minus a reserve of 21000 gas at `maxFeePerGas`.
function maxAfter(maxFeePerGas) {
    return formatEther(BALANCE_WEI - GAS * maxFeePerGas);
}

function el(id) {
    return global.document.getElementById(id);
}

function text(id) {
    return el(id).textContent;
}

// The ETH balance the node reports and the token rows the explorer reports,
// fetched and stored exactly where the popup stores them.
async function refreshWith(balanceWei, tokenItems = []) {
    mockNode.balanceWei = balanceWei;
    mockExplorer.items = tokenItems;
    state.wallets = [
        {
            type: "key",
            name: "Wallet 1",
            encryptedSecret: await encryptWithPassword(PRIVATE_KEY, PASSWORD),
            addresses: [{ address: HOLDER }],
        },
    ];
    state.selectedWallet = 0;
    state.selectedAddress = 0;
    await refreshBalances(
        state.wallets,
        "https://rpc.example.invalid",
        "https://blockscout.example/api/v2",
        state.trackedTokens,
        "mainnet",
    );
}

function tokenRow(value) {
    return {
        value: String(value),
        token: {
            type: "ERC-20",
            address_hash: TOKEN,
            symbol: "TOK",
            name: "Token",
            decimals: "18",
            holders_count: "50000",
        },
    };
}

// The confirmation screen Review leads to, once shown.
let confirmed = null;

// Open the Send screen for `token` ("ETH" or a token address), with the
// recipient entered.
function openSend(token = "ETH") {
    send.init({ showConfirmTx: (info) => (confirmed = info) });
    confirmTx.init({});
    send.resetSendValidation();
    state.selectedToken = token;
    el("send-to").value = RECIPIENT;
    el("send-amount").value = "";
}

async function pressMax() {
    await el("btn-send-max").handlers.get("click")();
}

// Press Review and show the confirmation screen with its fee estimate settled.
async function review() {
    await el("btn-send-review").handlers.get("click")();
    confirmTx.show(confirmed);
    await settle();
}

// show() starts the fee estimate without awaiting it; this lets it settle.
async function settle() {
    for (let i = 0; i < 10; i++) await new Promise((r) => setTimeout(r, 0));
}

function canSend() {
    return !el("btn-confirm-send").disabled;
}

beforeEach(() => {
    elements.clear();
    confirmed = null;
    state.selectedToken = null;
    state.trackedTokens = [];
    state.fraudContracts = [];
    state.currentView = null;
    mockNode.feeData = fees(20n * GWEI);
    mockNode.broadcast = [];
});

describe("Max on an ETH send", () => {
    test("fills in the exact balance minus the fee reserve", async () => {
        await refreshWith(BALANCE_WEI);
        openSend();
        send.updateSendBalance();
        expect(text("send-balance")).toBe("Current balance: 1.2345 ETH");
        await pressMax();
        // 1.234567890123456789 - 21000 * 20 gwei.
        expect(el("send-amount").value).toBe("1.234147890123456789");
    });

    test("leaves exactly the fee reserve behind, and the confirmation screen enables Send", async () => {
        await refreshWith(BALANCE_WEI);
        openSend();
        await pressMax();
        await review();
        expect(text("confirm-amount")).toBe(maxAfter(20n * GWEI) + " ETH");
        expect(el("confirm-errors").innerHTML).toBe("");
        expect(el("confirm-amount-fee-error").style.visibility).toBe("hidden");
        expect(canSend()).toBe(true);
    });

    test("re-derives the amount when the fee estimate changes", async () => {
        await refreshWith(BALANCE_WEI);
        openSend();
        await pressMax();
        expect(el("send-amount").value).toBe(maxAfter(20n * GWEI));

        // The fee rises between Max and the confirmation screen's estimate.
        // Kept, the Send screen's amount would be refused for want of funds.
        mockNode.feeData = fees(30n * GWEI);
        await review();
        expect(text("confirm-amount")).toBe(maxAfter(30n * GWEI) + " ETH");
        expect(canSend()).toBe(true);

        // And falls when the screen is shown again, as on reopening the popup.
        mockNode.feeData = fees(10n * GWEI);
        confirmTx.restore();
        await settle();
        expect(text("confirm-amount")).toBe(maxAfter(10n * GWEI) + " ETH");
        expect(canSend()).toBe(true);
    });

    test("is signed with the fee its amount leaves behind", async () => {
        await refreshWith(BALANCE_WEI);
        openSend();
        await pressMax();
        await review();
        // The fee the node quotes rises after the estimate. Fetched afresh
        // at signing, it would make amount plus fee more than the balance.
        mockNode.feeData = fees(25n * GWEI);
        el("confirm-tx-password").value = PASSWORD;
        await el("btn-confirm-send").handlers.get("click")();

        expect(mockNode.broadcast).toHaveLength(1);
        const tx = Transaction.from(mockNode.broadcast[0]);
        expect(tx.to).toBe(RECIPIENT);
        expect(tx.maxFeePerGas).toBe(20n * GWEI);
        expect(tx.value + tx.gasLimit * tx.maxFeePerGas).toBe(BALANCE_WEI);
    });

    test("says so instead of filling in an amount when the balance does not cover the fee", async () => {
        // 0.0001 ETH against a reserve of 0.00042 ETH.
        await refreshWith(100000000000000n);
        openSend();
        await pressMax();
        expect(el("send-amount").value).toBe("");
        expect(text("flash-msg")).toBe(
            "Your balance does not cover the network fee.",
        );
    });

    test("asks for the recipient first, since the fee depends on it", async () => {
        await refreshWith(BALANCE_WEI);
        openSend();
        el("send-to").value = "";
        await pressMax();
        expect(el("send-amount").value).toBe("");
        expect(text("flash-msg")).toBe(
            "Please enter a recipient address first.",
        );
    });

    test("typed over, is an ordinary amount the confirmation screen keeps", async () => {
        await refreshWith(BALANCE_WEI);
        openSend();
        await pressMax();
        el("send-amount").value = "0.5";
        el("send-amount").handlers.get("input")();
        mockNode.feeData = fees(30n * GWEI);
        await review();
        expect(text("confirm-amount")).toBe("0.5 ETH");
    });
});

describe("Max on a token send", () => {
    // 1234.567890123456789012 TOK; the Send screen shows 1234.5678.
    const TOKEN_UNITS = 1234567890123456789012n;

    test("fills in the whole token balance", async () => {
        await refreshWith(BALANCE_WEI, [tokenRow(TOKEN_UNITS)]);
        openSend(TOKEN);
        await pressMax();
        expect(el("send-amount").value).toBe("1234.567890123456789012");
        await review();
        expect(text("confirm-amount")).toBe("1234.567890123456789012 TOK");
        expect(canSend()).toBe(true);
    });

    test("is still refused when ETH cannot cover the fee", async () => {
        await refreshWith(0n, [tokenRow(TOKEN_UNITS)]);
        openSend(TOKEN);
        await pressMax();
        expect(el("send-amount").value).toBe("1234.567890123456789012");
        await review();
        expect(el("confirm-gas-error").style.visibility).toBe("visible");
        expect(canSend()).toBe(false);
    });

    test("says so when the token balance is unknown", async () => {
        // No scale from the explorer, the bundled list or a tracked token.
        const row = tokenRow(TOKEN_UNITS);
        delete row.token.decimals;
        await refreshWith(BALANCE_WEI, [row]);
        openSend(TOKEN);
        await pressMax();
        expect(el("send-amount").value).toBe("");
        expect(text("flash-msg")).toBe("This token's balance is unknown.");
    });

    test("says so when the token balance is zero", async () => {
        state.trackedTokens = [
            { address: TOKEN, symbol: "TOK", name: "Token", decimals: 18 },
        ];
        await refreshWith(BALANCE_WEI, [tokenRow(0n)]);
        openSend(TOKEN);
        await pressMax();
        expect(el("send-amount").value).toBe("");
        expect(text("flash-msg")).toBe("This token's balance is zero.");
    });
});