Add genesis_accounts module (#6708)

genesis/src/genesis_accounts.rs

@@ -0,0 +1,27 @@
+use solana_sdk::{account::Account, pubkey::Pubkey, system_program};
+
+pub(crate) fn create_genesis_accounts(
+    mint_pubkey: &Pubkey,
+    mint_lamports: u64,
+) -> Vec<(Pubkey, Account)> {
+    vec![
+        // the mint
+        (
+            *mint_pubkey,
+            Account::new(mint_lamports, 0, &system_program::id()),
+        ),
+    ]
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_create_genesis_accounts() {
+        let mint_lamports = 42;
+        let accounts = create_genesis_accounts(&Pubkey::default(), mint_lamports);
+        let genesis_lamports: u64 = accounts.iter().map(|(_, account)| account.lamports).sum();
+        assert_eq!(genesis_lamports, mint_lamports);
+    }
+}