Reorganize the repo structure (#2503)

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

test/token/ERC20/utils/TokenTimelock.test.js

@@ -0,0 +1,71 @@
+const { BN, expectRevert, time } = require('@openzeppelin/test-helpers');
+
+const { expect } = require('chai');
+
+const ERC20Mock = artifacts.require('ERC20Mock');
+const TokenTimelock = artifacts.require('TokenTimelock');
+
+contract('TokenTimelock', function (accounts) {
+  const [ beneficiary ] = accounts;
+
+  const name = 'My Token';
+  const symbol = 'MTKN';
+
+  const amount = new BN(100);
+
+  context('with token', function () {
+    beforeEach(async function () {
+      this.token = await ERC20Mock.new(name, symbol, beneficiary, 0); // We're not using the preminted tokens
+    });
+
+    it('rejects a release time in the past', async function () {
+      const pastReleaseTime = (await time.latest()).sub(time.duration.years(1));
+      await expectRevert(
+        TokenTimelock.new(this.token.address, beneficiary, pastReleaseTime),
+        'TokenTimelock: release time is before current time',
+      );
+    });
+
+    context('once deployed', function () {
+      beforeEach(async function () {
+        this.releaseTime = (await time.latest()).add(time.duration.years(1));
+        this.timelock = await TokenTimelock.new(this.token.address, beneficiary, this.releaseTime);
+        await this.token.mint(this.timelock.address, amount);
+      });
+
+      it('can get state', async function () {
+        expect(await this.timelock.token()).to.equal(this.token.address);
+        expect(await this.timelock.beneficiary()).to.equal(beneficiary);
+        expect(await this.timelock.releaseTime()).to.be.bignumber.equal(this.releaseTime);
+      });
+
+      it('cannot be released before time limit', async function () {
+        await expectRevert(this.timelock.release(), 'TokenTimelock: current time is before release time');
+      });
+
+      it('cannot be released just before time limit', async function () {
+        await time.increaseTo(this.releaseTime.sub(time.duration.seconds(3)));
+        await expectRevert(this.timelock.release(), 'TokenTimelock: current time is before release time');
+      });
+
+      it('can be released just after limit', async function () {
+        await time.increaseTo(this.releaseTime.add(time.duration.seconds(1)));
+        await this.timelock.release();
+        expect(await this.token.balanceOf(beneficiary)).to.be.bignumber.equal(amount);
+      });
+
+      it('can be released after time limit', async function () {
+        await time.increaseTo(this.releaseTime.add(time.duration.years(1)));
+        await this.timelock.release();
+        expect(await this.token.balanceOf(beneficiary)).to.be.bignumber.equal(amount);
+      });
+
+      it('cannot be released twice', async function () {
+        await time.increaseTo(this.releaseTime.add(time.duration.years(1)));
+        await this.timelock.release();
+        await expectRevert(this.timelock.release(), 'TokenTimelock: no tokens to release');
+        expect(await this.token.balanceOf(beneficiary)).to.be.bignumber.equal(amount);
+      });
+    });
+  });
+});