program-test: Add test for moving lamports (#30637)

program-test/tests/lamports.rs

@@ -0,0 +1,86 @@
+use {
+    solana_program_test::{processor, ProgramTest},
+    solana_sdk::{
+        account_info::{next_account_info, AccountInfo},
+        entrypoint::ProgramResult,
+        instruction::{AccountMeta, Instruction},
+        msg,
+        pubkey::Pubkey,
+        signature::{Keypair, Signer},
+        system_instruction,
+        transaction::Transaction,
+    },
+};
+
+fn move_lamports_process_instruction(
+    _program_id: &Pubkey,
+    accounts: &[AccountInfo],
+    _input: &[u8],
+) -> ProgramResult {
+    msg!("Processing lamports instruction");
+    let account_info_iter = &mut accounts.iter();
+    let source_info = next_account_info(account_info_iter)?;
+    let _other_info = next_account_info(account_info_iter)?;
+    let destination_info = next_account_info(account_info_iter)?;
+
+    let destination_lamports = destination_info.lamports();
+    **destination_info.lamports.borrow_mut() = destination_lamports
+        .checked_add(source_info.lamports())
+        .unwrap();
+    **source_info.lamports.borrow_mut() = 0;
+    Ok(())
+}
+
+#[tokio::test]
+async fn move_lamports() {
+    let move_lamports_program_id = Pubkey::new_unique();
+    let program_test = ProgramTest::new(
+        "move_lamports",
+        move_lamports_program_id,
+        processor!(move_lamports_process_instruction),
+    );
+
+    let lamports = 1_000_000_000;
+    let source = Keypair::new();
+    let mut context = program_test.start_with_context().await;
+    let instructions = vec![
+        system_instruction::create_account(
+            &context.payer.pubkey(),
+            &source.pubkey(),
+            lamports,
+            0,
+            &move_lamports_program_id,
+        ),
+        Instruction {
+            program_id: move_lamports_program_id,
+            accounts: vec![
+                AccountMeta::new(source.pubkey(), false),
+                AccountMeta::new(context.payer.pubkey(), false),
+                AccountMeta::new(context.payer.pubkey(), false),
+            ],
+            data: vec![],
+        },
+    ];
+
+    let transaction = Transaction::new_signed_with_payer(
+        &instructions,
+        Some(&context.payer.pubkey()),
+        &[&context.payer, &source],
+        context.last_blockhash,
+    );
+
+    context
+        .banks_client
+        .process_transaction(transaction)
+        .await
+        .unwrap();
+
+    assert_eq!(
+        context
+            .banks_client
+            .get_balance(source.pubkey())
+            .await
+            .unwrap(),
+        0
+    );
+}