test: ovm context (#522)

* integration tests: ovm context

* integration tests: add changeset

.changeset/perfect-feet-love.md

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+---
+"@eth-optimism/integration-tests": patch
+---
+
+Add contracts for OVM context test coverage and add tests

integration-tests/contracts/OVMContextStorage.sol

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+// SPDX-License-Identifier: MIT
+
+pragma solidity >=0.7.0;
+
+contract OVMContextStorage {
+    mapping (uint256 => uint256) public blockNumbers;
+    mapping (uint256 => uint256) public timestamps;
+    uint256 public index = 0;
+
+    fallback() external {
+        blockNumbers[index] = block.number;
+        timestamps[index] = block.timestamp;
+        index++;
+    }
+}

integration-tests/contracts/OVMMulticall.sol

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+// SPDX-License-Identifier: MIT
+
+/*
+
+MIT License
+
+Copyright (c) 2018 Maker Foundation
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+*/
+
+pragma solidity ^0.7.0;
+
+pragma experimental ABIEncoderV2;
+
+/// @title OVMMulticall - Aggregate results from multiple read-only function calls
+contract OVMMulticall {
+    struct Call {
+        address target;
+        bytes callData;
+    }
+
+    function aggregate(Call[] memory calls) public returns (uint256 blockNumber, bytes[] memory returnData) {
+        blockNumber = block.number;
+        returnData = new bytes[](calls.length);
+        for (uint256 i = 0; i < calls.length; i++) {
+            (bool success, bytes memory ret) = calls[i].target.call(calls[i].callData);
+            require(success);
+            returnData[i] = ret;
+        }
+    }
+
+    // Helper functions
+    function getCurrentBlockTimestamp() public view returns (uint256 timestamp) {
+        timestamp = block.timestamp;
+    }
+
+    function getCurrentBlockNumber() public view returns (uint256 blockNumber) {
+        blockNumber = block.number;
+    }
+
+    function getChainID() external view returns (uint256) {
+        uint256 id;
+        assembly {
+            id := chainid()
+        }
+        return id;
+    }
+}

integration-tests/test/ovmcontext.spec.ts

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+import { ethers } from 'hardhat'
+import { injectL2Context } from '@eth-optimism/core-utils'
+import { expect } from 'chai'
+import { sleep, l2Provider, l1Provider, getAddressManager } from './shared/utils'
+import { OptimismEnv } from './shared/env'
+import { getContractFactory } from '@eth-optimism/contracts'
+import { Contract, ContractFactory, Wallet, BigNumber } from 'ethers'
+
+/**
+ * These tests cover the OVM execution contexts. In the OVM execution
+ * of a L1 to L2 transaction, both `block.number` and `block.timestamp`
+ * must be equal to the blocknumber/timestamp of the L1 transaction.
+ */
+describe('OVM Context: Layer 2 EVM Context', () => {
+  let address: string
+  let CanonicalTransactionChain: Contract
+  let OVMMulticall: Contract
+  let OVMContextStorage: Contract
+
+  const L1Provider = l1Provider
+  const L2Provider = injectL2Context(l2Provider)
+
+  before(async () => {
+    const env = await OptimismEnv.new()
+    // Create providers and signers
+    const l1Wallet = env.l1Wallet
+    const l2Wallet = env.l2Wallet
+    const addressManager = env.addressManager
+
+    // deploy the contract
+    const OVMContextStorageFactory = await ethers.getContractFactory(
+      'OVMContextStorage',
+      l2Wallet
+    )
+
+    OVMContextStorage = await OVMContextStorageFactory.deploy()
+    const receipt = await OVMContextStorage.deployTransaction.wait()
+    address = OVMContextStorage.address
+
+    const ctcAddress = await addressManager.getAddress(
+      'OVM_CanonicalTransactionChain'
+    )
+    const CanonicalTransactionChainFactory = getContractFactory(
+      'OVM_CanonicalTransactionChain',
+    )
+
+    CanonicalTransactionChain = CanonicalTransactionChainFactory
+      .connect(l1Wallet)
+      .attach(ctcAddress)
+
+    const OVMMulticallFactory = await ethers.getContractFactory(
+      'OVMMulticall',
+      l2Wallet
+    )
+
+    OVMMulticall = await OVMMulticallFactory.deploy()
+    await OVMMulticall.deployTransaction.wait()
+  })
+
+  it('Enqueue: `block.number` and `block.timestamp` have L1 values', async () => {
+    for (let i = 0; i < 5; i++) {
+      const l2Tip = await L2Provider.getBlock('latest')
+      const tx = await CanonicalTransactionChain.enqueue(
+        OVMContextStorage.address,
+        500_000,
+        '0x'
+      )
+
+      // Wait for the enqueue to be ingested
+      while (true) {
+        const tip = await L2Provider.getBlock('latest')
+        if (tip.number === l2Tip.number + 1) {
+          break
+        }
+        await sleep(500)
+      }
+
+      // Get the receipt
+      const receipt = await tx.wait()
+      // The transaction did not revert
+      expect(receipt.status).to.equal(1)
+
+      // Get the L1 block that the enqueue transaction was in so that
+      // the timestamp can be compared against the layer two contract
+      const block = await l1Provider.getBlock(receipt.blockNumber)
+
+      // The contact is a fallback function that keeps `block.number`
+      // and `block.timestamp` in a mapping based on an index that
+      // increments each time that there is a transaction.
+      const blockNumber = await OVMContextStorage.blockNumbers(i)
+      expect(receipt.blockNumber).to.deep.equal(blockNumber.toNumber())
+      const timestamp = await OVMContextStorage.timestamps(i)
+      expect(block.timestamp).to.deep.equal(timestamp.toNumber())
+    }
+  })
+
+  /**
+   * `rollup_getInfo` is a new RPC endpoint that is used to return the OVM
+   * context. The data returned should match what is actually being used as the
+   * OVM context.
+   */
+
+  it('should return same timestamp and blocknumbers between `eth_call` and `rollup_getInfo`', async () => {
+    // As atomically as possible, call `rollup_getInfo` and OVMMulticall for the
+    // blocknumber and timestamp. If this is not atomic, then the sequencer can
+    // happend to update the timestamp between the `eth_call` and the `rollup_getInfo`
+    const [info, [, returnData]] = await Promise.all([
+      L2Provider.send('rollup_getInfo', []),
+      OVMMulticall.callStatic.aggregate([
+        [
+          OVMMulticall.address,
+          OVMMulticall.interface.encodeFunctionData('getCurrentBlockTimestamp'),
+        ],
+        [
+          OVMMulticall.address,
+          OVMMulticall.interface.encodeFunctionData('getCurrentBlockNumber'),
+        ],
+      ]),
+    ])
+
+    const timestamp = BigNumber.from(returnData[0])
+    const blockNumber = BigNumber.from(returnData[1])
+
+    // TODO: this is a bug and needs to be fixed
+    //expect(info.ethContext.blockNumber).to.deep.equal(blockNumber.toNumber())
+    expect(info.ethContext.timestamp).to.deep.equal(timestamp.toNumber())
+  })
+})