feat: make loader generic over hasher

crates/svm-test/src/svm.rs

@@ -1,4 +1,5 @@
-use std::collections::HashSet;
+use std::collections::{HashMap, HashSet};
+use std::hash::{BuildHasherDefault, DefaultHasher};
 
 use litesvm::types::SimulatedTransactionInfo;
 pub use litesvm::types::{FailedTransactionMetadata, TransactionMetadata, TransactionResult};
@@ -16,10 +17,12 @@ use solana_sdk::{
 use crate::spl::SplProgram;
 use crate::AccountLoader;
 
+pub type DefaultLoader = HashMap<Pubkey, Account, BuildHasherDefault<DefaultHasher>>;
+
 const PRE_LOADED: &[Pubkey] =
     &[ed25519_program::ID, secp256k1_program::ID, sysvar::instructions::ID];
 
-pub struct Svm<L> {
+pub struct Svm<L = DefaultLoader> {
     inner: litesvm::LiteSVM,
     pub loader: L,
     reserved_account_keys: ReservedAccountKeys,

crates/svm-test/src/traits.rs

@@ -42,7 +42,10 @@ pub trait AccountLoader {
     }
 }
 
-impl AccountLoader for std::collections::HashMap<Pubkey, Account> {
+impl<S> AccountLoader for std::collections::HashMap<Pubkey, Account, S>
+where
+    S: std::hash::BuildHasher,
+{
     fn load(&self, key: &Pubkey) -> Account {
         self.get(key).cloned().unwrap_or_default()
     }

crates/svm-test/tests/program_unit_test.rs

@@ -1,13 +1,12 @@
 //! These examples do not make use of `Harness` and only include local accounts
 //! & programs.
-use std::collections::HashMap;
-
 use expect_test::expect;
 use litesvm::types::SimulatedTransactionInfo;
 use solana_sdk::account::Account;
 use solana_sdk::instruction::Instruction;
 use solana_sdk::pubkey::Pubkey;
 use solana_sdk::transaction::Transaction;
+use svm_test::svm::DefaultLoader;
 use svm_test::utils::{test_payer_keypair, TEST_PAYER};
 use svm_test::Svm;
 
@@ -16,7 +15,7 @@ const MEMO_ID: Pubkey = Pubkey::new_from_array([1; 32]);
 #[test]
 fn memo() {
     // Load our program & give our test payer some funds.
-    let mut svm = Svm::new(HashMap::default());
+    let mut svm: Svm<DefaultLoader> = Svm::default();
     svm.load_program(MEMO_ID, "memo");
     svm.set(TEST_PAYER, Account { lamports: 10u64.pow(9), ..Default::default() });