In this lesson, we are going to see how we can test our project with rust, using cargo test.

In case you are stuck, you can checkout finished version from here

You can copy the cargo nocapture code used in the video below.

cargo test -- --nocapture

Here is the changes we have made to lib.rs in this video:

#[cfg(test)]
mod test {
    use super::*;
    use solana_program::{clock::Epoch, pubkey::Pubkey};
    use std::mem;

    #[test]
    fn test_counter() {
        let program_id = Pubkey::default();
        let key = Pubkey::default();
        let mut lamports = 0;
        let mut data = vec![0; mem::size_of::<u32>()];
        let owner = Pubkey::default();

        let account = AccountInfo::new(
            &key,
            false,
            true,
            &mut lamports,
            &mut data,
            &owner,
            false,
            Epoch::default(),
        );

        let accounts = vec![account];

        let increment_instruction_data: Vec<u8> = vec![0];
        let decrement_instruction_data: Vec<u8> = vec![1];
        let mut update_instruction_data: Vec<u8> = vec![2];
        let reset_instruction_data: Vec<u8> = vec![3];

        process_instruction(&program_id, &accounts, &increment_instruction_data).unwrap();

        assert_eq!(
            CounterAccount::try_from_slice(&accounts[0].data.borrow())
                .unwrap()
                .counter,
            1
        );

        process_instruction(&program_id, &accounts, &decrement_instruction_data).unwrap();

        assert_eq!(
            CounterAccount::try_from_slice(&accounts[0].data.borrow())
                .unwrap()
                .counter,
            0
        );

        let update_value = 33u32;
        update_instruction_data.extend_from_slice(&update_value.to_le_bytes());

        process_instruction(&program_id, &accounts, &update_instruction_data).unwrap();

        assert_eq!(
            CounterAccount::try_from_slice(&accounts[0].data.borrow())
                .unwrap()
                .counter,
            33
        );

        process_instruction(&program_id, &accounts, &reset_instruction_data).unwrap();

        assert_eq!(
            CounterAccount::try_from_slice(&accounts[0].data.borrow())
                .unwrap()
                .counter,
            0
        );
    }
}