feat(sdk): implement depositETH

Implements the depositETH function for the upcoming Optimism JS SDK.
Very basic functionality, only allows users to deposit to their own
accounts. We can consider adding the ability to deposit to other
accounts as part of a future PR.

packages/sdk/src/cross-chain-messenger.ts

@@ -44,7 +44,6 @@ export class CrossChainMessenger implements ICrossChainMessenger {
     overrides?: L1ToL2Overrides
   ): Promise<TransactionResponse> {
     const tx = await this.populateTransaction.sendMessage(message, overrides)
-
     if (message.direction === MessageDirection.L1_TO_L2) {
       return this.l1Signer.sendTransaction(tx)
     } else {
@@ -57,13 +56,13 @@ export class CrossChainMessenger implements ICrossChainMessenger {
     messageGasLimit: NumberLike,
     overrides?: Overrides
   ): Promise<TransactionResponse> {
-    const tx = await this.populateTransaction.resendMessage(
-      message,
-      messageGasLimit,
-      overrides
+    return this.l1Signer.sendTransaction(
+      await this.populateTransaction.resendMessage(
+        message,
+        messageGasLimit,
+        overrides
+      )
     )
-
-    return this.l1Signer.sendTransaction(tx)
   }
 
   public async finalizeMessage(
@@ -77,7 +76,9 @@ export class CrossChainMessenger implements ICrossChainMessenger {
     amount: NumberLike,
     overrides?: L1ToL2Overrides
   ): Promise<TransactionResponse> {
-    throw new Error('Not implemented')
+    return this.l1Signer.sendTransaction(
+      await this.populateTransaction.depositETH(amount, overrides)
+    )
   }
 
   public async withdrawETH(
@@ -148,7 +149,14 @@ export class CrossChainMessenger implements ICrossChainMessenger {
       amount: NumberLike,
       overrides?: L1ToL2Overrides
     ): Promise<TransactionRequest> => {
-      throw new Error('Not implemented')
+      return this.provider.contracts.l1.L1StandardBridge.populateTransaction.depositETH(
+        overrides?.l2GasLimit || 200000, // 200k gas is fine as a default
+        '0x', // No data
+        {
+          ...omit(overrides || {}, 'l2GasLimit', 'value'),
+          value: amount,
+        }
+      )
     },
 
     withdrawETH: async (
@@ -165,7 +173,6 @@ export class CrossChainMessenger implements ICrossChainMessenger {
       overrides?: L1ToL2Overrides
     ): Promise<BigNumber> => {
       const tx = await this.populateTransaction.sendMessage(message, overrides)
-
       if (message.direction === MessageDirection.L1_TO_L2) {
         return this.provider.l1Provider.estimateGas(tx)
       } else {
@@ -183,7 +190,6 @@ export class CrossChainMessenger implements ICrossChainMessenger {
         messageGasLimit,
         overrides
       )
-
       return this.provider.l1Provider.estimateGas(tx)
     },
 
@@ -198,7 +204,8 @@ export class CrossChainMessenger implements ICrossChainMessenger {
       amount: NumberLike,
       overrides?: L1ToL2Overrides
     ): Promise<BigNumber> => {
-      throw new Error('Not implemented')
+      const tx = await this.populateTransaction.depositETH(amount, overrides)
+      return this.provider.l1Provider.estimateGas(tx)
     },
 
     withdrawETH: async (

packages/sdk/test/contracts/MockBridge.sol

@@ -3,6 +3,13 @@ pragma solidity ^0.8.9;
 import { MockMessenger } from "./MockMessenger.sol";
 
 contract MockBridge {
+    event ETHDepositInitiated(
+        address indexed _from,
+        address indexed _to,
+        uint256 _amount,
+        bytes _data
+    );
+
     event ERC20DepositInitiated(
         address indexed _l1Token,
         address indexed _l2Token,
@@ -110,4 +117,19 @@ contract MockBridge {
     ) public {
         emit DepositFailed(_params.l1Token, _params.l2Token, _params.from, _params.to, _params.amount, _params.data);
     }
+
+    function depositETH(
+        uint32 _l2GasLimit,
+        bytes memory _data
+    )
+        public
+        payable
+    {
+        emit ETHDepositInitiated(
+            msg.sender,
+            msg.sender,
+            msg.value,
+            _data
+        );
+    }
 }

packages/sdk/test/cross-chain-messenger.spec.ts

@@ -211,4 +211,48 @@ describe('CrossChainMessenger', () => {
       it('should throw an error')
     })
   })
+
+  describe('depositETH', () => {
+    let l1Messenger: Contract
+    let l1Bridge: Contract
+    let provider: CrossChainProvider
+    let messenger: CrossChainMessenger
+    beforeEach(async () => {
+      l1Messenger = (await (
+        await ethers.getContractFactory('MockMessenger')
+      ).deploy()) as any
+      l1Bridge = (await (
+        await ethers.getContractFactory('MockBridge')
+      ).deploy(l1Messenger.address)) as any
+
+      provider = new CrossChainProvider({
+        l1Provider: ethers.provider,
+        l2Provider: ethers.provider,
+        l1ChainId: 31337,
+        contracts: {
+          l1: {
+            L1CrossDomainMessenger: l1Messenger.address,
+            L1StandardBridge: l1Bridge.address,
+          },
+        },
+      })
+
+      messenger = new CrossChainMessenger({
+        provider,
+        l1Signer,
+        l2Signer,
+      })
+    })
+
+    it('should trigger the deposit ETH function with the given amount', async () => {
+      await expect(messenger.depositETH(100000))
+        .to.emit(l1Bridge, 'ETHDepositInitiated')
+        .withArgs(
+          await l1Signer.getAddress(),
+          await l1Signer.getAddress(),
+          100000,
+          '0x'
+        )
+    })
+  })
 })