Fixes: #43

Description

The function had a math mistake, but the tests did not catch it because the tests were only checking for small slippage rates. When the slippage rate is 5% or less, the tests did not fail because the result was almost correct when rounded to the nearest whole number. However, when the slippage rate increased, the problem became more obvious.

Additionally, I made a change to the function to prevent a slippage rate of over 100%. It's impossible to lose more than 100% of your money, so setting a slippage rate of over 100% should generate an error.

I had to verify this change, so I modified the tests to reflect these updates.

Screen capture

Here is a manual test on the Uniswap Interface

Before	After

Test plan

Reproducing the error

1. Go to app.uniswap.org
2. Add two tokens to swap (Easier to test with two stablecoins like USDC & DAI)
3. Add Custom Slippage (Easier to test with a round number like 50%)
4. Open SwapDetailsDropdown see the incorrect number in the "Minimum output" row

Automated testing

• Run yarn test in your local env to make sure all test pass