Create failing test

Cargo.lock

@@ -2316,6 +2316,7 @@ dependencies = [
  "bincode 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.89 (registry+https://github.com/rust-lang/crates.io-index)",
+ "solana-runtime 0.12.0",
  "solana-sdk 0.12.0",
 ]
 

programs/system/Cargo.toml

@@ -14,6 +14,9 @@ log = "0.4.2"
 serde = "1.0.89"
 solana-sdk = { path = "../../sdk", version = "0.12.0" }
 
+[dev-dependencies]
+solana-runtime = { path = "../../runtime", version = "0.12.0" }
+
 [lib]
 name = "solana_system_program"
 
@@ -21,4 +24,3 @@ name = "solana_system_program"
 # allocates Rust memory.
 # cc: https://github.com/solana-labs/solana/issues/2004#issuecomment-444570081
 crate-type = ["lib"]
-

programs/system/tests/system.rs

@@ -0,0 +1,104 @@
+use solana_runtime::bank::{Bank, Result};
+use solana_sdk::genesis_block::GenesisBlock;
+use solana_sdk::pubkey::Pubkey;
+use solana_sdk::signature::{Keypair, KeypairUtil};
+use solana_sdk::system_program;
+use solana_sdk::system_transaction::SystemTransaction;
+
+struct SystemBank<'a> {
+    bank: &'a Bank,
+}
+
+impl<'a> SystemBank<'a> {
+    fn new(bank: &'a Bank) -> Self {
+        bank.add_native_program("solana_system_program", &system_program::id());
+        Self { bank }
+    }
+    fn create_account(&self, from_keypair: &Keypair, to: Pubkey, lamports: u64) -> Result<()> {
+        let blockhash = self.bank.last_blockhash();
+        let tx = SystemTransaction::new_account(from_keypair, to, lamports, blockhash, 0);
+        self.bank.process_transaction(&tx)
+    }
+    fn move_lamports(&self, from_keypair: &Keypair, to: Pubkey, lamports: u64) -> Result<()> {
+        let blockhash = self.bank.last_blockhash();
+        let tx = SystemTransaction::new_move(from_keypair, to, lamports, blockhash, 0);
+        self.bank.process_transaction(&tx)
+    }
+}
+
+#[test]
+fn test_create_cannot_overwrite_used_account() {
+    let (genesis_block, from_keypair) = GenesisBlock::new(10_000);
+    let bank = Bank::new(&genesis_block);
+    let system_bank = SystemBank::new(&bank);
+
+    // create_account on uninitialized account should work
+    let system_account = Keypair::new().pubkey();
+    system_bank
+        .create_account(&from_keypair, system_account, 100)
+        .unwrap();
+    assert_eq!(system_bank.bank.get_balance(&system_account), 100);
+
+    // Create an account assigned to another program
+    let other_account = Keypair::new().pubkey();
+    let program_id = Pubkey::new(&[9; 32]);
+    let tx = SystemTransaction::new_program_account(
+        &from_keypair,
+        other_account,
+        system_bank.bank.last_blockhash(),
+        1,
+        0,
+        program_id,
+        0,
+    );
+    system_bank.bank.process_transaction(&tx).unwrap();
+    assert_eq!(system_bank.bank.get_balance(&other_account), 1);
+    assert_eq!(
+        system_bank.bank.get_account(&other_account).unwrap().owner,
+        program_id
+    );
+
+    // create_account on an initialized account should fail
+    system_bank
+        .create_account(&from_keypair, other_account, 100)
+        .unwrap();
+    assert_eq!(system_bank.bank.get_balance(&other_account), 1);
+    assert_eq!(
+        system_bank.bank.get_account(&other_account).unwrap().owner,
+        program_id
+    );
+}
+#[test]
+fn test_move_can_fund_used_account() {
+    let (genesis_block, from_keypair) = GenesisBlock::new(10_000);
+    let bank = Bank::new(&genesis_block);
+    let system_bank = SystemBank::new(&bank);
+
+    // Create an account assigned to another program
+    let other_account = Keypair::new().pubkey();
+    let program_id = Pubkey::new(&[9; 32]);
+    let tx = SystemTransaction::new_program_account(
+        &from_keypair,
+        other_account,
+        system_bank.bank.last_blockhash(),
+        1,
+        0,
+        program_id,
+        0,
+    );
+    system_bank.bank.process_transaction(&tx).unwrap();
+    assert_eq!(system_bank.bank.get_balance(&other_account), 1);
+    assert_eq!(
+        system_bank.bank.get_account(&other_account).unwrap().owner,
+        program_id
+    );
+
+    system_bank
+        .move_lamports(&from_keypair, other_account, 100)
+        .unwrap();
+    assert_eq!(system_bank.bank.get_balance(&other_account), 101);
+    assert_eq!(
+        system_bank.bank.get_account(&other_account).unwrap().owner,
+        program_id
+    );
+}