Merge GSNContext into GSNRecipient (#1906)

* Merge GSNContext into GSNRecipient

* Update GSNRecipient.test.js

* Update GSNRecipient.sol

* Make GSNRecipient inherit from Context

(cherry picked from commit 1efa9f6281)

test/GSN/GSNRecipient.test.js

@@ -1,23 +1,94 @@
-const { balance, ether, expectRevert } = require('openzeppelin-test-helpers');
+const { balance, BN, constants, ether, expectEvent, expectRevert } = require('openzeppelin-test-helpers');
+const { ZERO_ADDRESS } = constants;
+
 const gsn = require('@openzeppelin/gsn-helpers');
 
 const { expect } = require('chai');
 
 const GSNRecipientMock = artifacts.require('GSNRecipientMock');
+const ContextMockCaller = artifacts.require('ContextMockCaller');
 
-contract('GSNRecipient', function ([_, payee]) {
+const { shouldBehaveLikeRegularContext } = require('./Context.behavior');
+
+contract('GSNRecipient', function ([_, payee, sender, newRelayHub]) {
   beforeEach(async function () {
     this.recipient = await GSNRecipientMock.new();
   });
 
-  it('returns the RelayHub address address', async function () {
-    expect(await this.recipient.getHubAddr()).to.equal('0xD216153c06E857cD7f72665E0aF1d7D82172F494');
-  });
-
   it('returns the compatible RelayHub version', async function () {
     expect(await this.recipient.relayHubVersion()).to.equal('1.0.0');
   });
 
+  describe('get/set RelayHub', function () {
+    const singletonRelayHub = '0xD216153c06E857cD7f72665E0aF1d7D82172F494';
+
+    it('initially returns the singleton instance address', async function () {
+      expect(await this.recipient.getHubAddr()).to.equal(singletonRelayHub);
+    });
+
+    it('can be upgraded to a new RelayHub', async function () {
+      const { logs } = await this.recipient.upgradeRelayHub(newRelayHub);
+      expectEvent.inLogs(logs, 'RelayHubChanged', { oldRelayHub: singletonRelayHub, newRelayHub });
+    });
+
+    it('cannot upgrade to the same RelayHub', async function () {
+      await expectRevert(
+        this.recipient.upgradeRelayHub(singletonRelayHub),
+        'GSNRecipient: new RelayHub is the current one'
+      );
+    });
+
+    it('cannot upgrade to the zero address', async function () {
+      await expectRevert(
+        this.recipient.upgradeRelayHub(ZERO_ADDRESS), 'GSNRecipient: new RelayHub is the zero address'
+      );
+    });
+
+    context('with new RelayHub', function () {
+      beforeEach(async function () {
+        await this.recipient.upgradeRelayHub(newRelayHub);
+      });
+
+      it('returns the new instance address', async function () {
+        expect(await this.recipient.getHubAddr()).to.equal(newRelayHub);
+      });
+    });
+  });
+
+  context('when called directly', function () {
+    beforeEach(async function () {
+      this.context = this.recipient; // The Context behavior expects the contract in this.context
+      this.caller = await ContextMockCaller.new();
+    });
+
+    shouldBehaveLikeRegularContext(sender);
+  });
+
+  context('when receiving a relayed call', function () {
+    beforeEach(async function () {
+      await gsn.fundRecipient(web3, { recipient: this.recipient.address });
+    });
+
+    describe('msgSender', function () {
+      it('returns the relayed transaction original sender', async function () {
+        const { tx } = await this.recipient.msgSender({ from: sender, useGSN: true });
+        await expectEvent.inTransaction(tx, GSNRecipientMock, 'Sender', { sender });
+      });
+    });
+
+    describe('msgData', function () {
+      it('returns the relayed transaction original data', async function () {
+        const integerValue = new BN('42');
+        const stringValue = 'OpenZeppelin';
+        const callData = this.recipient.contract.methods.msgData(integerValue.toString(), stringValue).encodeABI();
+
+        // The provider doesn't properly estimate gas for a relayed call, so we need to manually set a higher value
+        const { tx } = await this.recipient.msgData(integerValue, stringValue, { gas: 1000000, useGSN: true });
+        await expectEvent.inTransaction(tx, GSNRecipientMock, 'Data', { data: callData, integerValue, stringValue });
+      });
+    });
+  });
+
   context('with deposited funds', async function () {
     const amount = ether('1');