1. Swap ETH for WETH
2. Deposit some ETH into Aave
3. Borrow some asset with the ETH collateral
   1. Sell that borrowed asset. (Short selling)
4. Repay everything back

Testing:

Integration test: Kovan Unit tests: Mainnet-fork (Can do this because not working with oracles. If working with oracles deploy mocks on devopment network)