Dingirsu_Reflect!{

    impl D_Processer {
        pub fn A(
            program_id: &Pubkey, // Public key of the account the hello world program was loaded into
            accounts: &[AccountInfo], // The account to say hello to
            _instruction_data: &[u8], // Ignored, all helloworld instructions are hellos
        ) -> ProgramResult {
            msg!("A");
            print!("A");
            Ok(())
        }
        pub fn B(
            program_id: &Pubkey, // Public key of the account the hello world program was loaded into
            accounts: &[AccountInfo], // The account to say hello to
            _instruction_data: &[u8], // Ignored, all helloworld instructions are hellos
        ) -> ProgramResult {
            msg!("B");
            print!("B");
            Ok(())
        }
    }

}
#[cfg(test)]
..
let mut instruction_data: Vec<u8> = Vec::new();
let mut s=String::from("A\0");
let datas=s.as_bytes();
for  i in datas
{
    instruction_data.push(*i);
}
..
process_instruction(&program_id, &accounts, &instruction_data).unwrap();

    let t_data=Buffer.alloc(4);
    t_data[0]=65;
    t_data[1]=0;

    console.log('Saying hello to', prog.toBase58());
    const instruction = new TransactionInstruction({
      keys: [{pubkey: greetedPubkey, isSigner: false, isWritable: true}],
      programId:prog,
      data:t_data, // All instructions are hellos
    });
    let res= await sendAndConfirmTransaction(
      connection,
      new Transaction().add(instruction),
      [acc],
      {
        commitment: 'singleGossip',
        preflightCommitment: 'singleGossip',
      },
    );

    Program 54wzi12wkAq9vEtvxqVZBcgESm9aArrtzcReN7kJ8mwQ invoke [1]
    Hello!
    Reflect to function A
    Program 54wzi12wkAq9vEtvxqVZBcgESm9aArrtzcReN7kJ8mwQ consumed 966 of 200000 compute units
    Program 54wzi12wkAq9vEtvxqVZBcgESm9aArrtzcReN7kJ8mwQ success