Add ERC1167 library (minimal proxy) (#2449)

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

test/proxy/Clones.test.js

@@ -0,0 +1,54 @@
+const { expectEvent, expectRevert } = require('@openzeppelin/test-helpers');
+
+const shouldBehaveLikeClone = require('./Clones.behaviour');
+
+const ClonesMock = artifacts.require('ClonesMock');
+
+contract('Clones', function (accounts) {
+  describe('clone', function () {
+    shouldBehaveLikeClone(async (implementation, initData, opts = {}) => {
+      const factory = await ClonesMock.new();
+      const receipt = await factory.clone(implementation, initData, { value: opts.value });
+      const address = receipt.logs.find(({ event }) => event === 'NewInstance').args.instance;
+      return { address };
+    });
+  });
+
+  describe('cloneDeterministic', function () {
+    shouldBehaveLikeClone(async (implementation, initData, opts = {}) => {
+      const salt = web3.utils.randomHex(32);
+      const factory = await ClonesMock.new();
+      const receipt = await factory.cloneDeterministic(implementation, salt, initData, { value: opts.value });
+      const address = receipt.logs.find(({ event }) => event === 'NewInstance').args.instance;
+      return { address };
+    });
+
+    it('address already used', async function () {
+      const implementation = web3.utils.randomHex(20);
+      const salt = web3.utils.randomHex(32);
+      const factory = await ClonesMock.new();
+      // deploy once
+      expectEvent(
+        await factory.cloneDeterministic(implementation, salt, '0x'),
+        'NewInstance',
+      );
+      // deploy twice
+      await expectRevert(
+        factory.cloneDeterministic(implementation, salt, '0x'),
+        'ERC1167: create2 failed',
+      );
+    });
+
+    it('address prediction', async function () {
+      const implementation = web3.utils.randomHex(20);
+      const salt = web3.utils.randomHex(32);
+      const factory = await ClonesMock.new();
+      const predicted = await factory.predictDeterministicAddress(implementation, salt);
+      expectEvent(
+        await factory.cloneDeterministic(implementation, salt, '0x'),
+        'NewInstance',
+        { instance: predicted },
+      );
+    });
+  });
+});