Basic Balance Test

Now that we have the basics of our Pallet set up, let’s actually interact with it.

For that, we will go back to the main.rs file, and create our first #[test] which will play with the code we have written so far.

1. In your src/balances.rs file, add a new #[test] named fn init_balances():

   #![allow(unused)]
   fn main() {
   #[test]
   fn init_balances() { }
   }

2. To begin our test, we need to initialize a new instance of our Pallet:

   #![allow(unused)]
   fn main() {
   #[test]
   fn init_balances() {
   	let mut balances = super::Pallet::new();
   }
   }

   Note that we make this variable mut since we plan to mutate our state using our newly created API.

3. Finally, let’s check that our read and write APIs are working as expected:

   #![allow(unused)]
   fn main() {
   #[test]
   fn init_balances() {
   	let mut balances = super::Pallet::new();
   
   	assert_eq!(balances.balance(&"alice".to_string()), 0);
   	balances.set_balance(&"alice".to_string(), 100);
   	assert_eq!(balances.balance(&"alice".to_string()), 100);
   	assert_eq!(balances.balance(&"bob".to_string()), 0);
   }
   }

4. We can run our tests using cargo test, where hopefully you should see that it passes. There should be no compiler warnings now!

I hope at this point you can start to see the beginnings of your simple blockchain state machine.