Test if transaction is rejected by script verifier

Mock the state service to always return an error, this causes the script
verifier to fail getting the transparent unspent transaction output, and
should make the transaction validation fail.

zebra-consensus/src/transaction/tests.rs

@@ -1,4 +1,4 @@
-use std::{collections::HashMap, sync::Arc};
+use std::{collections::HashMap, io, sync::Arc};
 
 use tower::{service_fn, ServiceExt};
 
@@ -13,7 +13,7 @@ use zebra_chain::{
 
 use super::{check, Request, Verifier};
 
-use crate::{error::TransactionError, script};
+use crate::{error::TransactionError, script, BoxError};
 use color_eyre::eyre::Report;
 
 #[test]
@@ -241,3 +241,45 @@ async fn v5_transaction_is_accepted_after_nu5_activation() {
         assert_eq!(result, Ok(expected_hash));
     }
 }
+
+#[tokio::test]
+// TODO: Remove `should_panic` once the NU5 activation heights for testnet and mainnet have been
+// defined.
+#[should_panic]
+async fn v5_transaction_is_rejected_based_on_script() {
+    let network = Network::Mainnet;
+    let blocks = zebra_test::vectors::MAINNET_BLOCKS.iter();
+
+    let state_service = service_fn(|_| async {
+        Err(Box::new(io::Error::new(
+            io::ErrorKind::Other,
+            "Pretending the UTXO was not found",
+        )) as BoxError)
+    });
+
+    let script_verifier = script::Verifier::new(state_service);
+    let verifier = Verifier::new(network, script_verifier);
+
+    let transaction = fake_v5_transactions_for_network(network, blocks)
+        .rev()
+        .find(|transaction| {
+            !transaction.is_coinbase()
+                && transaction.inputs().is_empty()
+                && transaction.joinsplit_count() == 0
+                && transaction.sapling_spends_per_anchor().next().is_none()
+                && transaction.sapling_outputs().next().is_none()
+        })
+        .expect("At least one fake V5 coinbase transaction in the test vectors");
+
+    let result = verifier
+        .oneshot(Request::Block {
+            transaction: Arc::new(transaction),
+            known_utxos: Arc::new(HashMap::new()),
+            height: NetworkUpgrade::Nu5
+                .activation_height(network)
+                .expect("NU5 activation height is specified"),
+        })
+        .await;
+
+    assert!(result.is_err());
+}