Did you know Solana account roles (signer, writable) are transaction-wide?

transaction_roles.rs

use solana_program::{account_info::AccountInfo, entrypoint::ProgramResult, msg, pubkey::Pubkey};

solana_program::entrypoint!(process);

fn process(_program_id: &Pubkey, accounts: &[AccountInfo], _input: &[u8]) -> ProgramResult {
    let account = accounts.first().unwrap();
    msg!("KEY:          {}", account.key);
    msg!("IS_SIGNER:    {}", account.is_signer);
    msg!("IS_WRITABLE:  {}", account.is_writable);
    Ok(())
}

#[cfg(all(test, feature = "test-sbf"))]
mod tests {
    use {
        super::*,
        solana_sdk::{
            instruction::{AccountMeta, Instruction},
            signer::Signer,
            transaction::Transaction,
        },
        solana_program_test::{ProgramTest, ProgramTestContext, tokio},
    };

    const PROGRAM_ID: Pubkey = solana_program::pubkey!("BpC2Xr5dFTKZ2AHSZWVEdQN7RKgnnsEagG3Gcv13q62n");

    fn readonly_ix(key: &Pubkey) -> Instruction {
        let accounts = vec![AccountMeta::new_readonly(*key, false)];
        Instruction::new_with_bytes(PROGRAM_ID, &[], accounts)
    }

    fn signer_ix(key: &Pubkey) -> Instruction {
        let accounts = vec![AccountMeta::new_readonly(*key, true)];
        Instruction::new_with_bytes(PROGRAM_ID, &[], accounts)
    }

    fn writeable_signer_ix(key: &Pubkey) -> Instruction {
        let accounts = vec![AccountMeta::new(*key, true)];
        Instruction::new_with_bytes(PROGRAM_ID, &[], accounts)
    }

    #[tokio::test]
    async fn test() {
        let program_test = ProgramTest::new("test_program", PROGRAM_ID, None);

        let ProgramTestContext { banks_client, last_blockhash, payer, .. } = program_test.start_with_context().await;

        let tx = Transaction::new_signed_with_payer(
            &[
                readonly_ix(&payer.pubkey()),
                signer_ix(&payer.pubkey()),
                writeable_signer_ix(&payer.pubkey()),
            ],
            Some(&payer.pubkey()),
            &[&payer],
            last_blockhash,
        );

        banks_client.process_transaction(tx).await.unwrap();
    }
}