Add tests and benches for epoch processing

eth2/state_processing/benches/benches.rs

@@ -0,0 +1,28 @@
+use criterion::Criterion;
+use criterion::{black_box, criterion_group, criterion_main};
+// use env_logger::{Builder, Env};
+use state_processing::SlotProcessable;
+use types::{beacon_state::BeaconStateBuilder, ChainSpec, Hash256};
+
+fn epoch_processing(c: &mut Criterion) {
+    // Builder::from_env(Env::default().default_filter_or("debug")).init();
+
+    let mut builder = BeaconStateBuilder::with_random_validators(8);
+    builder.spec = ChainSpec::few_validators();
+
+    builder.genesis().unwrap();
+    builder.teleport_to_end_of_epoch(builder.spec.genesis_epoch + 4);
+
+    let state = builder.build().unwrap();
+
+    c.bench_function("epoch processing", move |b| {
+        let spec = &builder.spec;
+        b.iter_with_setup(
+            || state.clone(),
+            |mut state| black_box(state.per_slot_processing(Hash256::zero(), spec).unwrap()),
+        )
+    });
+}
+
+criterion_group!(benches, epoch_processing,);
+criterion_main!(benches);