Add (failing) attester_slashing tests

tests/ef_tests/src/cases/operations_attester_slashing.rs

@@ -0,0 +1,42 @@
+use super::*;
+use crate::case_result::compare_beacon_state_results_without_caches;
+use serde_derive::Deserialize;
+use state_processing::per_block_processing::process_attester_slashings;
+use types::{AttesterSlashing, BeaconState, EthSpec};
+
+#[derive(Debug, Clone, Deserialize)]
+pub struct OperationsAttesterSlashing<E: EthSpec> {
+    pub description: String,
+    #[serde(bound = "E: EthSpec")]
+    pub pre: BeaconState<E>,
+    pub attester_slashing: AttesterSlashing,
+    #[serde(bound = "E: EthSpec")]
+    pub post: Option<BeaconState<E>>,
+}
+
+impl<E: EthSpec> YamlDecode for OperationsAttesterSlashing<E> {
+    fn yaml_decode(yaml: &String) -> Result<Self, Error> {
+        Ok(serde_yaml::from_str(&yaml.as_str()).unwrap())
+    }
+}
+
+impl<E: EthSpec> Case for OperationsAttesterSlashing<E> {
+    fn description(&self) -> String {
+        self.description.clone()
+    }
+
+    fn result(&self, _case_index: usize) -> Result<(), Error> {
+        let mut state = self.pre.clone();
+        let attester_slashing = self.attester_slashing.clone();
+        let mut expected = self.post.clone();
+
+        // Processing requires the epoch cache.
+        state.build_all_caches(&E::spec()).unwrap();
+
+        let result = process_attester_slashings(&mut state, &[attester_slashing], &E::spec());
+
+        let mut result = result.and_then(|_| Ok(state));
+
+        compare_beacon_state_results_without_caches(&mut result, &mut expected)
+    }
+}