Context

Closes #1102

YieldDeposit is not a great contract name, happy to hear better suggestions.

Tasks

https://nexusmutual.slack.com/archives/C06R21K595F/p1711633388892209

Cover buy

• user deposits 100 weETH which provides a cover equivalent to 1000 weETH
• write down the current oracle value of weETH/ETH, ex 1.2 ETH for 1 weETH
• cover amount is 1200 ETH
• [write down the timestamp]
• mint an NFT

User withdrawal

• pull the latest oracle value
• withdrawable amount = deposit * initial_rate / current_rate
  • ex: 100 -> 100 * 1.2 / 1.3 = 92.30769230769231

Changes proposed in this pull request

• YieldDeposit contract (need a better name!)
  • deposit
  • withdraw
  • withdrawAvailableYield - manager only

Test plan

• deposit unit tests
• withdraw unit tests
• withdrawAvailableYield unit tests
• getCurrentTokenPrice calculation unit tests
• getCurrentTokenValue calculation unit tests
• user coverAmount unit tests
• price rate unit tests
  • price rate moving up withdraw / withdrawAvailableYield
  • price rate going down withdraw / withdrawAvailableYield

Checklist

• Rebased the base branch
• Attached corresponding Github issue
• Prefixed the name with the type of change (i.e. feat, chore, test)
• Performed a self-review of my own code
• Followed the style guidelines of this project
• Made corresponding changes to the documentation
• Didn't generate new warnings
• Didn't generate failures on existing tests
• Added tests that prove my fix is effective or that my feature works

Review

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• 🔨 = I believe this should be changed.
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• 🚀 = Feedback