From 3dc22e7323fb97c8a36c57cc4c475ea589d0fa32 Mon Sep 17 00:00:00 2001
From: Greg Fitzgerald <greg@solana.com>
Date: Thu, 7 Mar 2019 13:42:01 -0700
Subject: [PATCH] Simulate auto-creation of system accounts

---
 programs/budget/src/budget_program.rs | 35 ++++++---------------------
 runtime/src/runtime.rs                |  5 +++-
 2 files changed, 12 insertions(+), 28 deletions(-)

diff --git a/programs/budget/src/budget_program.rs b/programs/budget/src/budget_program.rs
index 56a05f970a..cd5abaf92b 100644
--- a/programs/budget/src/budget_program.rs
+++ b/programs/budget/src/budget_program.rs
@@ -168,7 +168,7 @@ mod test {
 
     fn process_transaction(
         tx: &Transaction,
-        tx_accounts: &mut [Account],
+        tx_accounts: &mut Vec<Account>,
     ) -> Result<(), BudgetError> {
         runtime::process_transaction(tx, tx_accounts, process_instruction)
     }
@@ -192,12 +192,7 @@ mod test {
 
     #[test]
     fn test_unsigned_witness_key() {
-        let mut accounts = vec![
-            Account::new(1, 0, system_program::id()),
-            Account::new(0, 0, system_program::id()),
-            Account::new(0, 0, system_program::id()),
-            Account::new(0, 0, system_program::id()),
-        ];
+        let mut accounts = vec![Account::new(1, 0, system_program::id())];
 
         // Initialize BudgetState
         let from = Keypair::new();
@@ -232,12 +227,7 @@ mod test {
 
     #[test]
     fn test_unsigned_timestamp() {
-        let mut accounts = vec![
-            Account::new(1, 0, system_program::id()),
-            Account::new(0, 0, system_program::id()),
-            Account::new(0, 0, system_program::id()),
-            Account::new(0, 0, system_program::id()),
-        ];
+        let mut accounts = vec![Account::new(1, 0, system_program::id())];
 
         // Initialize BudgetState
         let from = Keypair::new();
@@ -273,11 +263,7 @@ mod test {
 
     #[test]
     fn test_transfer_on_date() {
-        let mut accounts = vec![
-            Account::new(1, 0, system_program::id()),
-            Account::new(0, 0, system_program::id()),
-            Account::new(0, 0, system_program::id()),
-        ];
+        let mut accounts = vec![Account::new(1, 0, system_program::id())];
         let from_account = 0;
         let contract_account = 1;
         let to_account = 2;
@@ -349,11 +335,7 @@ mod test {
     }
     #[test]
     fn test_cancel_transfer() {
-        let mut accounts = vec![
-            Account::new(1, 0, system_program::id()),
-            Account::new(0, 0, system_program::id()),
-            Account::new(0, 0, system_program::id()),
-        ];
+        let mut accounts = vec![Account::new(1, 0, system_program::id())];
         let from_account = 0;
         let contract_account = 1;
         let pay_account = 2;
@@ -386,8 +368,7 @@ mod test {
         // nothing should be changed because apply witness didn't finalize a payment
         assert_eq!(accounts[from_account].lamports, 0);
         assert_eq!(accounts[contract_account].lamports, 1);
-        // this is the `to.pubkey()` account
-        assert_eq!(accounts[pay_account].lamports, 0);
+        assert_eq!(accounts.get(pay_account), None);
 
         // Now, cancel the transaction. from gets her funds back
         let tx = BudgetTransaction::new_signature(
@@ -399,7 +380,7 @@ mod test {
         process_transaction(&tx, &mut accounts).unwrap();
         assert_eq!(accounts[from_account].lamports, 1);
         assert_eq!(accounts[contract_account].lamports, 0);
-        assert_eq!(accounts[pay_account].lamports, 0);
+        assert_eq!(accounts.get(pay_account), None);
 
         // try to replay the cancel contract
         let tx = BudgetTransaction::new_signature(
@@ -414,6 +395,6 @@ mod test {
         );
         assert_eq!(accounts[from_account].lamports, 1);
         assert_eq!(accounts[contract_account].lamports, 0);
-        assert_eq!(accounts[pay_account].lamports, 0);
+        assert_eq!(accounts.get(pay_account), None);
     }
 }
diff --git a/runtime/src/runtime.rs b/runtime/src/runtime.rs
index 58ac9bab1a..fc9deecad3 100644
--- a/runtime/src/runtime.rs
+++ b/runtime/src/runtime.rs
@@ -192,12 +192,15 @@ pub fn execute_transaction(
 /// for easier usage and better stack traces.
 pub fn process_transaction<F, E>(
     tx: &Transaction,
-    tx_accounts: &mut [Account],
+    tx_accounts: &mut Vec<Account>,
     process_instruction: F,
 ) -> Result<(), E>
 where
     F: Fn(&Pubkey, &mut [KeyedAccount], &[u8]) -> Result<(), E>,
 {
+    for _ in tx_accounts.len()..tx.account_keys.len() {
+        tx_accounts.push(Account::new(0, 0, system_program::id()));
+    }
     for (i, ix) in tx.instructions.iter().enumerate() {
         let mut ix_accounts = get_subset_unchecked_mut(tx_accounts, &ix.accounts);
         let mut keyed_accounts: Vec<_> = ix