Update docs

test/utils/Multicall.test.js

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+const { BN } = require('@openzeppelin/test-helpers');
+const { expectRevertCustomError } = require('../helpers/customError');
+
+const ERC20MulticallMock = artifacts.require('$ERC20MulticallMock');
+
+contract('Multicall', function (accounts) {
+  const [deployer, alice, bob] = accounts;
+  const amount = 12000;
+
+  beforeEach(async function () {
+    this.multicallToken = await ERC20MulticallMock.new('name', 'symbol');
+    await this.multicallToken.$_mint(deployer, amount);
+  });
+
+  it('batches function calls', async function () {
+    expect(await this.multicallToken.balanceOf(alice)).to.be.bignumber.equal(new BN('0'));
+    expect(await this.multicallToken.balanceOf(bob)).to.be.bignumber.equal(new BN('0'));
+
+    await this.multicallToken.multicall(
+      [
+        this.multicallToken.contract.methods.transfer(alice, amount / 2).encodeABI(),
+        this.multicallToken.contract.methods.transfer(bob, amount / 3).encodeABI(),
+      ],
+      { from: deployer },
+    );
+
+    expect(await this.multicallToken.balanceOf(alice)).to.be.bignumber.equal(new BN(amount / 2));
+    expect(await this.multicallToken.balanceOf(bob)).to.be.bignumber.equal(new BN(amount / 3));
+  });
+
+  it('returns an array with the result of each call', async function () {
+    const MulticallTest = artifacts.require('MulticallTest');
+    const multicallTest = await MulticallTest.new({ from: deployer });
+    await this.multicallToken.transfer(multicallTest.address, amount, { from: deployer });
+    expect(await this.multicallToken.balanceOf(multicallTest.address)).to.be.bignumber.equal(new BN(amount));
+
+    const recipients = [alice, bob];
+    const amounts = [amount / 2, amount / 3].map(n => new BN(n));
+
+    await multicallTest.checkReturnValues(this.multicallToken.address, recipients, amounts);
+  });
+
+  it('reverts previous calls', async function () {
+    expect(await this.multicallToken.balanceOf(alice)).to.be.bignumber.equal(new BN('0'));
+
+    const call = this.multicallToken.multicall(
+      [
+        this.multicallToken.contract.methods.transfer(alice, amount).encodeABI(),
+        this.multicallToken.contract.methods.transfer(bob, amount).encodeABI(),
+      ],
+      { from: deployer },
+    );
+
+    await expectRevertCustomError(call, 'ERC20InsufficientBalance', [deployer, 0, amount]);
+    expect(await this.multicallToken.balanceOf(alice)).to.be.bignumber.equal(new BN('0'));
+  });
+
+  it('bubbles up revert reasons', async function () {
+    const call = this.multicallToken.multicall(
+      [
+        this.multicallToken.contract.methods.transfer(alice, amount).encodeABI(),
+        this.multicallToken.contract.methods.transfer(bob, amount).encodeABI(),
+      ],
+      { from: deployer },
+    );
+
+    await expectRevertCustomError(call, 'ERC20InsufficientBalance', [deployer, 0, amount]);
+  });
+});