diff --git a/nssa/src/public_transaction/encoding.rs b/nssa/src/public_transaction/encoding.rs
index 371f1b5..9e7c550 100644
--- a/nssa/src/public_transaction/encoding.rs
+++ b/nssa/src/public_transaction/encoding.rs
@@ -121,7 +121,7 @@ impl WitnessSet {
 
 impl PublicTransaction {
     pub fn to_bytes(&self) -> Vec<u8> {
-        let mut bytes = self.message().to_bytes();
+        let mut bytes = self.message.to_bytes();
         bytes.extend_from_slice(&self.witness_set().to_bytes());
         bytes
     }
diff --git a/nssa/src/public_transaction/mod.rs b/nssa/src/public_transaction/mod.rs
index ce9ae9e..bd2f760 100644
--- a/nssa/src/public_transaction/mod.rs
+++ b/nssa/src/public_transaction/mod.rs
@@ -7,7 +7,3 @@ mod transaction;
 pub use message::Message;
 pub use witness_set::WitnessSet;
 pub use transaction::PublicTransaction;
-
-#[cfg(test)]
-pub use transaction::tests;
-
diff --git a/nssa/src/public_transaction/transaction.rs b/nssa/src/public_transaction/transaction.rs
index 8d6bc47..59f8bd8 100644
--- a/nssa/src/public_transaction/transaction.rs
+++ b/nssa/src/public_transaction/transaction.rs
@@ -16,8 +16,8 @@ use crate::{
 
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct PublicTransaction {
-    message: Message,
-    witness_set: WitnessSet,
+    pub(crate) message: Message,
+    pub(crate) witness_set: WitnessSet,
 }
 
 impl PublicTransaction {
@@ -115,69 +115,3 @@ impl PublicTransaction {
     }
 }
 
-#[cfg(test)]
-pub mod tests {
-    use crate::{
-        Address, PrivateKey, PublicKey, PublicTransaction,
-        program::Program,
-        public_transaction::{Message, WitnessSet, witness_set},
-    };
-
-    pub fn transaction_for_tests() -> PublicTransaction {
-        let key1 = PrivateKey::try_new([1; 32]).unwrap();
-        let key2 = PrivateKey::try_new([2; 32]).unwrap();
-        let addr1 = Address::from_public_key(&PublicKey::new(&key1));
-        let addr2 = Address::from_public_key(&PublicKey::new(&key2));
-        let nonces = vec![5, 99];
-        let instruction = 1337;
-        let message = Message::try_new(
-            Program::authenticated_transfer_program().id(),
-            vec![addr1, addr2],
-            nonces,
-            instruction,
-        )
-        .unwrap();
-
-        let witness_set = WitnessSet::for_message(&message, &[&key1, &key2]);
-        PublicTransaction::new(message, witness_set)
-    }
-
-    #[test]
-    fn test_new_constructor() {
-        let tx = transaction_for_tests();
-        let message = tx.message().clone();
-        let witness_set = tx.witness_set().clone();
-        let tx_from_constructor = PublicTransaction::new(message.clone(), witness_set.clone());
-        assert_eq!(tx_from_constructor.message, message);
-        assert_eq!(tx_from_constructor.witness_set, witness_set);
-    }
-
-    #[test]
-    fn test_message_getter() {
-        let tx = transaction_for_tests();
-        assert_eq!(&tx.message, tx.message());
-    }
-
-    #[test]
-    fn test_witness_set_getter() {
-        let tx = transaction_for_tests();
-        assert_eq!(&tx.witness_set, tx.witness_set());
-    }
-
-    #[test]
-    fn test_signer_addresses() {
-        let tx = transaction_for_tests();
-        let expected_signer_addresses = vec![
-            Address::new([
-                27, 132, 197, 86, 123, 18, 100, 64, 153, 93, 62, 213, 170, 186, 5, 101, 215, 30,
-                24, 52, 96, 72, 25, 255, 156, 23, 245, 233, 213, 221, 7, 143,
-            ]),
-            Address::new([
-                77, 75, 108, 209, 54, 16, 50, 202, 155, 210, 174, 185, 217, 0, 170, 77, 69, 217,
-                234, 216, 10, 201, 66, 51, 116, 196, 81, 167, 37, 77, 7, 102,
-            ]),
-        ];
-        let signer_addresses = tx.signer_addresses();
-        assert_eq!(signer_addresses, expected_signer_addresses);
-    }
-}
diff --git a/nssa/src/tests/public_transaction_tests.rs b/nssa/src/tests/public_transaction_tests.rs
index 3401857..07c3c80 100644
--- a/nssa/src/tests/public_transaction_tests.rs
+++ b/nssa/src/tests/public_transaction_tests.rs
@@ -1,11 +1,81 @@
 use sha2::{Digest, digest::FixedOutput};
 
 use crate::{
-    Address, PrivateKey, PublicKey, PublicTransaction,
+    Address, PrivateKey, PublicKey, PublicTransaction, Signature, V01State,
+    error::NssaError,
     program::Program,
-    public_transaction::{Message, WitnessSet, tests::transaction_for_tests},
+    public_transaction::{Message, WitnessSet},
 };
 
+fn keys_for_tests() -> (PrivateKey, PrivateKey, Address, Address) {
+    let key1 = PrivateKey::try_new([1; 32]).unwrap();
+    let key2 = PrivateKey::try_new([2; 32]).unwrap();
+    let addr1 = Address::from_public_key(&PublicKey::new(&key1));
+    let addr2 = Address::from_public_key(&PublicKey::new(&key2));
+    (key1, key2, addr1, addr2)
+}
+
+fn state_for_tests() -> V01State {
+    let (key1, key2, addr1, addr2) = keys_for_tests();
+    let initial_data = [(*addr1.value(), 10000), (*addr2.value(), 20000)];
+    V01State::new_with_genesis_accounts(&initial_data)
+}
+
+fn transaction_for_tests() -> PublicTransaction {
+    let (key1, key2, addr1, addr2) = keys_for_tests();
+    let nonces = vec![0, 0];
+    let instruction = 1337;
+    let message = Message::try_new(
+        Program::authenticated_transfer_program().id(),
+        vec![addr1, addr2],
+        nonces,
+        instruction,
+    )
+    .unwrap();
+
+    let witness_set = WitnessSet::for_message(&message, &[&key1, &key2]);
+    PublicTransaction::new(message, witness_set)
+}
+
+#[test]
+fn test_new_constructor() {
+    let tx = transaction_for_tests();
+    let message = tx.message().clone();
+    let witness_set = tx.witness_set().clone();
+    let tx_from_constructor = PublicTransaction::new(message.clone(), witness_set.clone());
+    assert_eq!(tx_from_constructor.message, message);
+    assert_eq!(tx_from_constructor.witness_set, witness_set);
+}
+
+#[test]
+fn test_message_getter() {
+    let tx = transaction_for_tests();
+    assert_eq!(&tx.message, tx.message());
+}
+
+#[test]
+fn test_witness_set_getter() {
+    let tx = transaction_for_tests();
+    assert_eq!(&tx.witness_set, tx.witness_set());
+}
+
+#[test]
+fn test_signer_addresses() {
+    let tx = transaction_for_tests();
+    let expected_signer_addresses = vec![
+        Address::new([
+            27, 132, 197, 86, 123, 18, 100, 64, 153, 93, 62, 213, 170, 186, 5, 101, 215, 30, 24,
+            52, 96, 72, 25, 255, 156, 23, 245, 233, 213, 221, 7, 143,
+        ]),
+        Address::new([
+            77, 75, 108, 209, 54, 16, 50, 202, 155, 210, 174, 185, 217, 0, 170, 77, 69, 217, 234,
+            216, 10, 201, 66, 51, 116, 196, 81, 167, 37, 77, 7, 102,
+        ]),
+    ];
+    let signer_addresses = tx.signer_addresses();
+    assert_eq!(signer_addresses, expected_signer_addresses);
+}
+
 #[test]
 fn test_public_transaction_encoding_bytes_roundtrip() {
     let tx = transaction_for_tests();
@@ -26,3 +96,100 @@ fn test_hash_is_sha256_of_transaction_bytes() {
     };
     assert_eq!(hash, expected_hash);
 }
+
+#[test]
+fn test_address_list_cant_have_duplicates() {
+    let (key1, _, addr1, _) = keys_for_tests();
+    let state = state_for_tests();
+    let nonces = vec![0, 0];
+    let instruction = 1337;
+    let message = Message::try_new(
+        Program::authenticated_transfer_program().id(),
+        vec![addr1.clone(), addr1],
+        nonces,
+        instruction,
+    )
+    .unwrap();
+
+    let witness_set = WitnessSet::for_message(&message, &[&key1, &key1]);
+    let tx = PublicTransaction::new(message, witness_set);
+    let result = tx.validate_and_compute_post_states(&state);
+    assert!(matches!(result, Err(NssaError::InvalidInput(_))))
+}
+
+#[test]
+fn test_number_of_nonces_must_match_number_of_signatures() {
+    let (key1, key2, addr1, addr2) = keys_for_tests();
+    let state = state_for_tests();
+    let nonces = vec![0];
+    let instruction = 1337;
+    let message = Message::try_new(
+        Program::authenticated_transfer_program().id(),
+        vec![addr1, addr2],
+        nonces,
+        instruction,
+    )
+    .unwrap();
+
+    let witness_set = WitnessSet::for_message(&message, &[&key1, &key2]);
+    let tx = PublicTransaction::new(message, witness_set);
+    let result = tx.validate_and_compute_post_states(&state);
+    assert!(matches!(result, Err(NssaError::InvalidInput(_))))
+}
+
+#[test]
+fn test_all_signatures_must_be_valid() {
+    let (key1, key2, addr1, addr2) = keys_for_tests();
+    let state = state_for_tests();
+    let nonces = vec![0, 0];
+    let instruction = 1337;
+    let message = Message::try_new(
+        Program::authenticated_transfer_program().id(),
+        vec![addr1, addr2],
+        nonces,
+        instruction,
+    )
+    .unwrap();
+
+    let mut witness_set = WitnessSet::for_message(&message, &[&key1, &key2]);
+    witness_set.signatures_and_public_keys[0].0 = Signature { value: [1; 64] };
+    let tx = PublicTransaction::new(message, witness_set);
+    let result = tx.validate_and_compute_post_states(&state);
+    assert!(matches!(result, Err(NssaError::InvalidInput(_))))
+}
+
+#[test]
+fn test_nonces_must_match_the_state_current_nonces() {
+    let (key1, key2, addr1, addr2) = keys_for_tests();
+    let state = state_for_tests();
+    let nonces = vec![0, 1];
+    let instruction = 1337;
+    let message = Message::try_new(
+        Program::authenticated_transfer_program().id(),
+        vec![addr1, addr2],
+        nonces,
+        instruction,
+    )
+    .unwrap();
+
+    let witness_set = WitnessSet::for_message(&message, &[&key1, &key2]);
+    let tx = PublicTransaction::new(message, witness_set);
+    let result = tx.validate_and_compute_post_states(&state);
+    assert!(matches!(result, Err(NssaError::InvalidInput(_))))
+}
+
+#[test]
+fn test_program_id_must_belong_to_bulitin_program_ids() {
+    let (key1, key2, addr1, addr2) = keys_for_tests();
+    let state = state_for_tests();
+    let nonces = vec![0, 0];
+    let instruction = 1337;
+    let unknown_program_id = [0xdeadbeef; 8];
+    let message =
+        Message::try_new(unknown_program_id, vec![addr1, addr2], nonces, instruction).unwrap();
+
+    let witness_set = WitnessSet::for_message(&message, &[&key1, &key2]);
+    let tx = PublicTransaction::new(message, witness_set);
+    let result = tx.validate_and_compute_post_states(&state);
+    assert!(matches!(result, Err(NssaError::InvalidInput(_))))
+}