## Pranking and Impersonating in Solidity Tests Sometimes when we're writing tests, we want to pretend to be somebody else, or we want to prank. Our account, the default account, is going to be who deployed this address. But we should probably check that the non-owner cannot withdraw. We will need to get some other random user. We can assign a value to `RANDOM_USER`: ```python RANDOM_USER = boa.env.generate_address('non-owner') ``` Now we can write a test called `test_non_owner_cannot_withdraw`: ```python def test_non_owner_cannot_withdraw(coffee, account): # Arrange boa.env.set_balance(account.address, SEND_VALUE) coffee.fund(value=SEND_VALUE) # Act with boa.prank(RANDOM_USER): boa.reverts('You are not the owner!', coffee.withdraw()) ``` We are arranging by funding the account. Then, we are pranking a random user, and we are reverting. Let's test it out with a terminal command: ```bash mox test ``` This is how you pretend to be some other user. This is how you set the current user to somebody else random. And this is how you revert. Let's keep going. We will check to see if it doesn't work. Let's also check to see how it does work. We can do a test called `test_owner_can_withdraw`. ```python def test_owner_can_withdraw(coffee, account): # Arrange boa.env.set_balance(account.address, SEND_VALUE) coffee.fund(value=SEND_VALUE) # Act with boa.env.prank(coffee.OWNER): coffee.withdraw() # Assert assert coffee.funders() == boa.env.get_balance(coffee.OWNER) == 0 ``` Usually, just to make sure, I like to also prank that I am actually the owner here. So, I might do something like `boa.env.set_balance` and then `coffee.OWNER`. We then do `coffee.fund(value=SEND_VALUE)`. Finally, we assert that `boa.env.get_balance(coffee.address)` is equal to zero. Let's test this out. ```bash mox test ``` We ran into an error "unsupported type". Let's scroll up and see what line it's mad at me about. It looks like it's on the `assert` line about getting the balance of `coffee.address`. Let's change the `assert` line, to instead be: ```python assert coffee.funders() == 0 ``` Let's run `mox test` again and see if it passes.