diff --git a/eth2/utils/tree_hash/src/impls.rs b/eth2/utils/tree_hash/src/impls.rs
index 88293196e..9f09f50ce 100644
--- a/eth2/utils/tree_hash/src/impls.rs
+++ b/eth2/utils/tree_hash/src/impls.rs
@@ -1,5 +1,5 @@
 use super::*;
-use ethereum_types::H256;
+use ethereum_types::{H256, U128, U256};
 
 macro_rules! impl_for_bitsize {
     ($type: ident, $bit_size: expr) => {
@@ -73,6 +73,46 @@ macro_rules! impl_for_u8_array {
 impl_for_u8_array!(4);
 impl_for_u8_array!(32);
 
+impl TreeHash for U128 {
+    fn tree_hash_type() -> TreeHashType {
+        TreeHashType::Basic
+    }
+
+    fn tree_hash_packed_encoding(&self) -> Vec<u8> {
+        let mut result = vec![0; 16];
+        self.to_little_endian(&mut result);
+        result
+    }
+
+    fn tree_hash_packing_factor() -> usize {
+        2
+    }
+
+    fn tree_hash_root(&self) -> Vec<u8> {
+        merkle_root(&self.tree_hash_packed_encoding(), 0)
+    }
+}
+
+impl TreeHash for U256 {
+    fn tree_hash_type() -> TreeHashType {
+        TreeHashType::Basic
+    }
+
+    fn tree_hash_packed_encoding(&self) -> Vec<u8> {
+        let mut result = vec![0; 32];
+        self.to_little_endian(&mut result);
+        result
+    }
+
+    fn tree_hash_packing_factor() -> usize {
+        1
+    }
+
+    fn tree_hash_root(&self) -> Vec<u8> {
+        merkle_root(&self.tree_hash_packed_encoding(), 0)
+    }
+}
+
 impl TreeHash for H256 {
     fn tree_hash_type() -> TreeHashType {
         TreeHashType::Vector
diff --git a/tests/ef_tests/Cargo.toml b/tests/ef_tests/Cargo.toml
index ba6aca259..2f1dea11d 100644
--- a/tests/ef_tests/Cargo.toml
+++ b/tests/ef_tests/Cargo.toml
@@ -18,7 +18,9 @@ serde_derive = "1.0"
 serde_repr = "0.1"
 serde_yaml = "0.8"
 eth2_ssz = "0.1"
+eth2_ssz_derive = "0.1"
 tree_hash = "0.1"
+tree_hash_derive = "0.2"
 state_processing = { path = "../../eth2/state_processing" }
 swap_or_not_shuffle = { path = "../../eth2/utils/swap_or_not_shuffle" }
 types = { path = "../../eth2/types" }
diff --git a/tests/ef_tests/src/cases.rs b/tests/ef_tests/src/cases.rs
index ed00f0ffe..279086b68 100644
--- a/tests/ef_tests/src/cases.rs
+++ b/tests/ef_tests/src/cases.rs
@@ -9,6 +9,7 @@ mod bls_g2_compressed;
 mod bls_g2_uncompressed;
 mod bls_priv_to_pub;
 mod bls_sign_msg;
+mod common;
 mod epoch_processing;
 mod genesis_initialization;
 mod genesis_validity;
@@ -25,6 +26,7 @@ pub use bls_g2_compressed::*;
 pub use bls_g2_uncompressed::*;
 pub use bls_priv_to_pub::*;
 pub use bls_sign_msg::*;
+pub use common::SszStaticType;
 pub use epoch_processing::*;
 pub use genesis_initialization::*;
 pub use genesis_validity::*;
@@ -61,20 +63,6 @@ pub trait Case: Debug + Sync {
     fn result(&self, case_index: usize) -> Result<(), Error>;
 }
 
-pub trait BlsCase: serde::de::DeserializeOwned {}
-
-impl<T: BlsCase> YamlDecode for T {
-    fn yaml_decode(string: &str) -> Result<Self, Error> {
-        serde_yaml::from_str(string).map_err(|e| Error::FailedToParseTest(format!("{:?}", e)))
-    }
-}
-
-impl<T: BlsCase> LoadCase for T {
-    fn load_from_dir(path: &Path) -> Result<Self, Error> {
-        Self::yaml_decode_file(&path.join("data.yaml"))
-    }
-}
-
 #[derive(Debug)]
 pub struct Cases<T> {
     pub test_cases: Vec<T>,
diff --git a/tests/ef_tests/src/cases/bls_aggregate_pubkeys.rs b/tests/ef_tests/src/cases/bls_aggregate_pubkeys.rs
index c94e14495..13c2fea17 100644
--- a/tests/ef_tests/src/cases/bls_aggregate_pubkeys.rs
+++ b/tests/ef_tests/src/cases/bls_aggregate_pubkeys.rs
@@ -1,5 +1,6 @@
 use super::*;
 use crate::case_result::compare_result;
+use crate::cases::common::BlsCase;
 use bls::{AggregatePublicKey, PublicKey};
 use serde_derive::Deserialize;
 
diff --git a/tests/ef_tests/src/cases/bls_aggregate_sigs.rs b/tests/ef_tests/src/cases/bls_aggregate_sigs.rs
index 882ad7220..22fa197df 100644
--- a/tests/ef_tests/src/cases/bls_aggregate_sigs.rs
+++ b/tests/ef_tests/src/cases/bls_aggregate_sigs.rs
@@ -1,5 +1,6 @@
 use super::*;
 use crate::case_result::compare_result;
+use crate::cases::common::BlsCase;
 use bls::{AggregateSignature, Signature};
 use serde_derive::Deserialize;
 
diff --git a/tests/ef_tests/src/cases/bls_g2_compressed.rs b/tests/ef_tests/src/cases/bls_g2_compressed.rs
index f8381f5a7..1a9f1d561 100644
--- a/tests/ef_tests/src/cases/bls_g2_compressed.rs
+++ b/tests/ef_tests/src/cases/bls_g2_compressed.rs
@@ -1,5 +1,6 @@
 use super::*;
 use crate::case_result::compare_result;
+use crate::cases::common::BlsCase;
 use bls::{compress_g2, hash_on_g2};
 use serde_derive::Deserialize;
 
diff --git a/tests/ef_tests/src/cases/bls_g2_uncompressed.rs b/tests/ef_tests/src/cases/bls_g2_uncompressed.rs
index 962b6aac3..3eae29967 100644
--- a/tests/ef_tests/src/cases/bls_g2_uncompressed.rs
+++ b/tests/ef_tests/src/cases/bls_g2_uncompressed.rs
@@ -1,5 +1,6 @@
 use super::*;
 use crate::case_result::compare_result;
+use crate::cases::common::BlsCase;
 use bls::hash_on_g2;
 use serde_derive::Deserialize;
 
@@ -9,18 +10,14 @@ pub struct BlsG2UncompressedInput {
     pub domain: String,
 }
 
+impl BlsCase for BlsG2UncompressedInput {}
+
 #[derive(Debug, Clone, Deserialize)]
 pub struct BlsG2Uncompressed {
     pub input: BlsG2UncompressedInput,
     pub output: Vec<Vec<String>>,
 }
 
-impl YamlDecode for BlsG2Uncompressed {
-    fn yaml_decode(yaml: &str) -> Result<Self, Error> {
-        Ok(serde_yaml::from_str(yaml).unwrap())
-    }
-}
-
 impl Case for BlsG2Uncompressed {
     fn result(&self, _case_index: usize) -> Result<(), Error> {
         // Convert message and domain to required types
diff --git a/tests/ef_tests/src/cases/bls_priv_to_pub.rs b/tests/ef_tests/src/cases/bls_priv_to_pub.rs
index 869a0891c..016e04dd1 100644
--- a/tests/ef_tests/src/cases/bls_priv_to_pub.rs
+++ b/tests/ef_tests/src/cases/bls_priv_to_pub.rs
@@ -1,5 +1,6 @@
 use super::*;
 use crate::case_result::compare_result;
+use crate::cases::common::BlsCase;
 use bls::{PublicKey, SecretKey};
 use serde_derive::Deserialize;
 
diff --git a/tests/ef_tests/src/cases/bls_sign_msg.rs b/tests/ef_tests/src/cases/bls_sign_msg.rs
index 18e90896b..7ee109f81 100644
--- a/tests/ef_tests/src/cases/bls_sign_msg.rs
+++ b/tests/ef_tests/src/cases/bls_sign_msg.rs
@@ -1,5 +1,6 @@
 use super::*;
 use crate::case_result::compare_result;
+use crate::cases::common::BlsCase;
 use bls::{SecretKey, Signature};
 use serde_derive::Deserialize;
 
diff --git a/tests/ef_tests/src/cases/common.rs b/tests/ef_tests/src/cases/common.rs
new file mode 100644
index 000000000..8e787f157
--- /dev/null
+++ b/tests/ef_tests/src/cases/common.rs
@@ -0,0 +1,72 @@
+use crate::cases::LoadCase;
+use crate::decode::yaml_decode_file;
+use crate::error::Error;
+use serde_derive::Deserialize;
+use ssz::{Decode, Encode};
+use ssz_derive::{Decode, Encode};
+use std::convert::TryFrom;
+use std::fmt::Debug;
+use std::path::Path;
+use tree_hash::TreeHash;
+
+/// Trait for all BLS cases to eliminate some boilerplate.
+pub trait BlsCase: serde::de::DeserializeOwned {}
+
+impl<T: BlsCase> LoadCase for T {
+    fn load_from_dir(path: &Path) -> Result<Self, Error> {
+        yaml_decode_file(&path.join("data.yaml"))
+    }
+}
+
+/// Macro to wrap U128 and U256 so they deserialize correctly.
+macro_rules! uint_wrapper {
+    ($wrapper_name:ident, $wrapped_type:ty) => {
+        #[derive(Debug, Clone, Copy, Default, PartialEq, Decode, Encode, Deserialize)]
+        #[serde(try_from = "String")]
+        pub struct $wrapper_name {
+            pub x: $wrapped_type,
+        }
+
+        impl TryFrom<String> for $wrapper_name {
+            type Error = String;
+
+            fn try_from(s: String) -> Result<Self, Self::Error> {
+                <$wrapped_type>::from_dec_str(&s)
+                    .map(|x| Self { x })
+                    .map_err(|e| format!("{:?}", e))
+            }
+        }
+
+        impl tree_hash::TreeHash for $wrapper_name {
+            fn tree_hash_type() -> tree_hash::TreeHashType {
+                <$wrapped_type>::tree_hash_type()
+            }
+
+            fn tree_hash_packed_encoding(&self) -> Vec<u8> {
+                self.x.tree_hash_packed_encoding()
+            }
+
+            fn tree_hash_packing_factor() -> usize {
+                <$wrapped_type>::tree_hash_packing_factor()
+            }
+
+            fn tree_hash_root(&self) -> Vec<u8> {
+                self.x.tree_hash_root()
+            }
+        }
+    };
+}
+
+uint_wrapper!(TestU128, ethereum_types::U128);
+uint_wrapper!(TestU256, ethereum_types::U256);
+
+/// Trait alias for all deez bounds
+pub trait SszStaticType:
+    serde::de::DeserializeOwned + Decode + Encode + TreeHash + Clone + PartialEq + Debug + Sync
+{
+}
+
+impl<T> SszStaticType for T where
+    T: serde::de::DeserializeOwned + Decode + Encode + TreeHash + Clone + PartialEq + Debug + Sync
+{
+}
diff --git a/tests/ef_tests/src/cases/epoch_processing.rs b/tests/ef_tests/src/cases/epoch_processing.rs
index d79b5fc48..2a2dde629 100644
--- a/tests/ef_tests/src/cases/epoch_processing.rs
+++ b/tests/ef_tests/src/cases/epoch_processing.rs
@@ -1,9 +1,9 @@
 use super::*;
 use crate::bls_setting::BlsSetting;
 use crate::case_result::compare_beacon_state_results_without_caches;
+use crate::decode::{ssz_decode_file, yaml_decode_file};
 use crate::type_name;
 use crate::type_name::TypeName;
-use crate::yaml_decode::{ssz_decode_file, yaml_decode_file};
 use serde_derive::Deserialize;
 use state_processing::per_epoch_processing::{
     errors::EpochProcessingError, process_crosslinks, process_final_updates,
diff --git a/tests/ef_tests/src/cases/genesis_initialization.rs b/tests/ef_tests/src/cases/genesis_initialization.rs
index 4f0fa4296..bd0507b9d 100644
--- a/tests/ef_tests/src/cases/genesis_initialization.rs
+++ b/tests/ef_tests/src/cases/genesis_initialization.rs
@@ -1,6 +1,6 @@
 use super::*;
 use crate::case_result::compare_beacon_state_results_without_caches;
-use crate::yaml_decode::{ssz_decode_file, yaml_decode_file};
+use crate::decode::{ssz_decode_file, yaml_decode_file};
 use serde_derive::Deserialize;
 use state_processing::initialize_beacon_state_from_eth1;
 use std::path::PathBuf;
diff --git a/tests/ef_tests/src/cases/genesis_validity.rs b/tests/ef_tests/src/cases/genesis_validity.rs
index efebe5e11..3a1b9e267 100644
--- a/tests/ef_tests/src/cases/genesis_validity.rs
+++ b/tests/ef_tests/src/cases/genesis_validity.rs
@@ -1,5 +1,5 @@
 use super::*;
-use crate::yaml_decode::{ssz_decode_file, yaml_decode_file};
+use crate::decode::{ssz_decode_file, yaml_decode_file};
 use serde_derive::Deserialize;
 use state_processing::is_valid_genesis_state;
 use std::path::{Path, PathBuf};
diff --git a/tests/ef_tests/src/cases/operations.rs b/tests/ef_tests/src/cases/operations.rs
index e86e6f598..7b4ffff98 100644
--- a/tests/ef_tests/src/cases/operations.rs
+++ b/tests/ef_tests/src/cases/operations.rs
@@ -1,8 +1,8 @@
 use super::*;
 use crate::bls_setting::BlsSetting;
 use crate::case_result::compare_beacon_state_results_without_caches;
+use crate::decode::{ssz_decode_file, yaml_decode_file};
 use crate::type_name::TypeName;
-use crate::yaml_decode::{ssz_decode_file, yaml_decode_file};
 use serde_derive::Deserialize;
 use ssz::Decode;
 use state_processing::per_block_processing::{
diff --git a/tests/ef_tests/src/cases/sanity_blocks.rs b/tests/ef_tests/src/cases/sanity_blocks.rs
index d88d8f295..9fadea42e 100644
--- a/tests/ef_tests/src/cases/sanity_blocks.rs
+++ b/tests/ef_tests/src/cases/sanity_blocks.rs
@@ -1,7 +1,7 @@
 use super::*;
 use crate::bls_setting::BlsSetting;
 use crate::case_result::compare_beacon_state_results_without_caches;
-use crate::yaml_decode::{ssz_decode_file, yaml_decode_file};
+use crate::decode::{ssz_decode_file, yaml_decode_file};
 use serde_derive::Deserialize;
 use state_processing::{
     per_block_processing, per_slot_processing, BlockInvalid, BlockProcessingError,
diff --git a/tests/ef_tests/src/cases/sanity_slots.rs b/tests/ef_tests/src/cases/sanity_slots.rs
index a66f1c2c4..34acb1105 100644
--- a/tests/ef_tests/src/cases/sanity_slots.rs
+++ b/tests/ef_tests/src/cases/sanity_slots.rs
@@ -1,7 +1,7 @@
 use super::*;
 use crate::bls_setting::BlsSetting;
 use crate::case_result::compare_beacon_state_results_without_caches;
-use crate::yaml_decode::{ssz_decode_file, yaml_decode_file};
+use crate::decode::{ssz_decode_file, yaml_decode_file};
 use serde_derive::Deserialize;
 use state_processing::per_slot_processing;
 use std::path::PathBuf;
diff --git a/tests/ef_tests/src/cases/shuffling.rs b/tests/ef_tests/src/cases/shuffling.rs
index c0595e584..2fe632e84 100644
--- a/tests/ef_tests/src/cases/shuffling.rs
+++ b/tests/ef_tests/src/cases/shuffling.rs
@@ -1,5 +1,6 @@
 use super::*;
 use crate::case_result::compare_result;
+use crate::decode::yaml_decode_file;
 use serde_derive::Deserialize;
 use std::marker::PhantomData;
 use swap_or_not_shuffle::{get_permutated_index, shuffle_list};
@@ -13,15 +14,9 @@ pub struct Shuffling<T> {
     _phantom: PhantomData<T>,
 }
 
-impl<T> YamlDecode for Shuffling<T> {
-    fn yaml_decode(yaml: &str) -> Result<Self, Error> {
-        Ok(serde_yaml::from_str(yaml).unwrap())
-    }
-}
-
 impl<T: EthSpec> LoadCase for Shuffling<T> {
     fn load_from_dir(path: &Path) -> Result<Self, Error> {
-        Self::yaml_decode_file(&path.join("mapping.yaml"))
+        yaml_decode_file(&path.join("mapping.yaml"))
     }
 }
 
diff --git a/tests/ef_tests/src/cases/ssz_generic.rs b/tests/ef_tests/src/cases/ssz_generic.rs
index 05b96ad7d..5f9cd3faf 100644
--- a/tests/ef_tests/src/cases/ssz_generic.rs
+++ b/tests/ef_tests/src/cases/ssz_generic.rs
@@ -1,11 +1,12 @@
 use super::*;
-use crate::cases::ssz_static::{check_serialization, check_tree_hash, SszStaticType};
-use crate::yaml_decode::yaml_decode_file;
+use crate::cases::common::{SszStaticType, TestU128, TestU256};
+use crate::cases::ssz_static::{check_serialization, check_tree_hash};
+use crate::decode::yaml_decode_file;
 use serde_derive::Deserialize;
 use std::fs;
 use std::path::{Path, PathBuf};
 use types::typenum::*;
-use types::{BitList, BitVector, FixedVector, VariableList};
+use types::{BitList, BitVector, FixedVector};
 
 #[derive(Debug, Clone, Deserialize)]
 struct Metadata {
@@ -51,9 +52,8 @@ macro_rules! type_dispatch {
             "uint16" => type_dispatch!($function, ($($arg),*), $base_ty, <$($param_ty,)* u16>, $($rest)*),
             "uint32" => type_dispatch!($function, ($($arg),*), $base_ty, <$($param_ty,)* u32>, $($rest)*),
             "uint64" => type_dispatch!($function, ($($arg),*), $base_ty, <$($param_ty,)* u64>, $($rest)*),
-            // FIXME(michael): implement tree hash for big ints
-            // "uint128" => type_dispatch!($function, ($($arg),*), $base_ty, <$($param_ty,)* etherum_types::U128>, $($rest)*),
-            // "uint256" => type_dispatch!($function, ($($arg),*), $base_ty, <$($param_ty,)* ethereum_types::U256>, $($rest)*),
+            "uint128" => type_dispatch!($function, ($($arg),*), $base_ty, <$($param_ty,)* TestU128>, $($rest)*),
+            "uint256" => type_dispatch!($function, ($($arg),*), $base_ty, <$($param_ty,)* TestU256>, $($rest)*),
             _ => { println!("unsupported: {}", $value); Ok(()) },
         }
     };
@@ -121,9 +121,13 @@ impl Case for SszGeneric {
                 )?;
             }
             "bitlist" => {
-                let limit = parts[1];
+                let mut limit = parts[1];
 
-                // FIXME(michael): mark length "no" cases as known failures
+                // Test format is inconsistent, pretend the limit is 32 (arbitrary)
+                // https://github.com/ethereum/eth2.0-spec-tests
+                if limit == "no" {
+                    limit = "32";
+                }
 
                 type_dispatch!(
                     ssz_generic_test,
diff --git a/tests/ef_tests/src/cases/ssz_static.rs b/tests/ef_tests/src/cases/ssz_static.rs
index f9f59cc4b..d1c9b1048 100644
--- a/tests/ef_tests/src/cases/ssz_static.rs
+++ b/tests/ef_tests/src/cases/ssz_static.rs
@@ -1,10 +1,10 @@
 use super::*;
 use crate::case_result::compare_result;
+use crate::cases::common::SszStaticType;
+use crate::decode::yaml_decode_file;
 use serde_derive::Deserialize;
-use ssz::{Decode, Encode};
-use std::fmt::Debug;
 use std::fs;
-use tree_hash::{SignedRoot, TreeHash};
+use tree_hash::SignedRoot;
 use types::Hash256;
 
 #[derive(Debug, Clone, Deserialize)]
@@ -13,12 +13,6 @@ struct SszStaticRoots {
     signing_root: Option<String>,
 }
 
-impl YamlDecode for SszStaticRoots {
-    fn yaml_decode(yaml: &str) -> Result<Self, Error> {
-        Ok(serde_yaml::from_str(yaml).unwrap())
-    }
-}
-
 #[derive(Debug, Clone)]
 pub struct SszStatic<T> {
     roots: SszStaticRoots,
@@ -33,26 +27,11 @@ pub struct SszStaticSR<T> {
     value: T,
 }
 
-// Trait alias for all deez bounds
-pub trait SszStaticType:
-    serde::de::DeserializeOwned + Decode + Encode + TreeHash + Clone + PartialEq + Debug + Sync
-{
-}
-
-impl<T> SszStaticType for T where
-    T: serde::de::DeserializeOwned + Decode + Encode + TreeHash + Clone + PartialEq + Debug + Sync
-{
-}
-
 fn load_from_dir<T: SszStaticType>(path: &Path) -> Result<(SszStaticRoots, Vec<u8>, T), Error> {
-    // FIXME: set description/name
-    let roots = SszStaticRoots::yaml_decode_file(&path.join("roots.yaml"))?;
-
+    // FIXME(michael): set description/name
+    let roots = yaml_decode_file(&path.join("roots.yaml"))?;
     let serialized = fs::read(&path.join("serialized.ssz")).expect("serialized.ssz exists");
-
-    let yaml = fs::read_to_string(&path.join("value.yaml")).expect("value.yaml exists");
-    let value =
-        serde_yaml::from_str(&yaml).map_err(|e| Error::FailedToParseTest(format!("{:?}", e)))?;
+    let value = yaml_decode_file(&path.join("value.yaml"))?;
 
     Ok((roots, serialized, value))
 }
diff --git a/tests/ef_tests/src/decode.rs b/tests/ef_tests/src/decode.rs
new file mode 100644
index 000000000..c1ea6fb3b
--- /dev/null
+++ b/tests/ef_tests/src/decode.rs
@@ -0,0 +1,31 @@
+use super::*;
+use std::fs;
+use std::path::Path;
+
+pub fn yaml_decode<T: serde::de::DeserializeOwned>(string: &str) -> Result<T, Error> {
+    serde_yaml::from_str(string).map_err(|e| Error::FailedToParseTest(format!("{:?}", e)))
+}
+
+pub fn yaml_decode_file<T: serde::de::DeserializeOwned>(path: &Path) -> Result<T, Error> {
+    fs::read_to_string(path)
+        .map_err(|e| {
+            Error::FailedToParseTest(format!("Unable to load {}: {:?}", path.display(), e))
+        })
+        .and_then(|s| yaml_decode(&s))
+}
+
+pub fn ssz_decode_file<T: ssz::Decode>(path: &Path) -> Result<T, Error> {
+    fs::read(path)
+        .map_err(|e| {
+            Error::FailedToParseTest(format!("Unable to load {}: {:?}", path.display(), e))
+        })
+        .and_then(|s| {
+            T::from_ssz_bytes(&s).map_err(|e| {
+                Error::FailedToParseTest(format!(
+                    "Unable to parse SSZ at {}: {:?}",
+                    path.display(),
+                    e
+                ))
+            })
+        })
+}
diff --git a/tests/ef_tests/src/lib.rs b/tests/ef_tests/src/lib.rs
index bcf7c77a0..719bfc1aa 100644
--- a/tests/ef_tests/src/lib.rs
+++ b/tests/ef_tests/src/lib.rs
@@ -7,13 +7,12 @@ pub use cases::{
 };
 pub use error::Error;
 pub use handler::*;
-pub use yaml_decode::YamlDecode;
 
 mod bls_setting;
 mod case_result;
 mod cases;
+mod decode;
 mod error;
 mod handler;
 mod results;
 mod type_name;
-mod yaml_decode;
diff --git a/tests/ef_tests/src/results.rs b/tests/ef_tests/src/results.rs
index 20e59f7b3..4f5513a9a 100644
--- a/tests/ef_tests/src/results.rs
+++ b/tests/ef_tests/src/results.rs
@@ -80,7 +80,8 @@ pub fn print_results(
 
         println!("-------");
         println!(
-            "case ({}) from {} failed with {}:",
+            "case {} ({}) from {} failed with {}:",
+            failure.case_index,
             failure.desc,
             failure.path.display(),
             error.name()
diff --git a/tests/ef_tests/src/yaml_decode.rs b/tests/ef_tests/src/yaml_decode.rs
deleted file mode 100644
index 83a162930..000000000
--- a/tests/ef_tests/src/yaml_decode.rs
+++ /dev/null
@@ -1,93 +0,0 @@
-use super::*;
-use ethereum_types::{U128, U256};
-use std::fs;
-use std::path::Path;
-use types::Fork;
-
-pub fn yaml_decode<T: serde::de::DeserializeOwned>(string: &str) -> Result<T, Error> {
-    serde_yaml::from_str(string).map_err(|e| Error::FailedToParseTest(format!("{:?}", e)))
-}
-
-pub fn yaml_decode_file<T: serde::de::DeserializeOwned>(path: &Path) -> Result<T, Error> {
-    fs::read_to_string(path)
-        .map_err(|e| {
-            Error::FailedToParseTest(format!("Unable to load {}: {:?}", path.display(), e))
-        })
-        .and_then(|s| yaml_decode(&s))
-}
-
-pub fn ssz_decode_file<T: ssz::Decode>(path: &Path) -> Result<T, Error> {
-    fs::read(path)
-        .map_err(|e| {
-            Error::FailedToParseTest(format!("Unable to load {}: {:?}", path.display(), e))
-        })
-        .and_then(|s| {
-            T::from_ssz_bytes(&s).map_err(|e| {
-                Error::FailedToParseTest(format!(
-                    "Unable to parse SSZ at {}: {:?}",
-                    path.display(),
-                    e
-                ))
-            })
-        })
-}
-
-pub trait YamlDecode: Sized {
-    /// Decode an object from the test specification YAML.
-    fn yaml_decode(string: &str) -> Result<Self, Error>;
-
-    fn yaml_decode_file(path: &Path) -> Result<Self, Error> {
-        fs::read_to_string(path)
-            .map_err(|e| {
-                Error::FailedToParseTest(format!("Unable to load {}: {:?}", path.display(), e))
-            })
-            .and_then(|s| Self::yaml_decode(&s))
-    }
-}
-
-/// Basic types can general be decoded with the `parse` fn if they implement `str::FromStr`.
-macro_rules! impl_via_parse {
-    ($ty: ty) => {
-        impl YamlDecode for $ty {
-            fn yaml_decode(string: &str) -> Result<Self, Error> {
-                string
-                    .parse::<Self>()
-                    .map_err(|e| Error::FailedToParseTest(format!("{:?}", e)))
-            }
-        }
-    };
-}
-
-impl_via_parse!(u8);
-impl_via_parse!(u16);
-impl_via_parse!(u32);
-impl_via_parse!(u64);
-
-/// Some `ethereum-types` methods have a `str::FromStr` implementation that expects `0x`-prefixed:
-/// hex, so we use `from_dec_str` instead.
-macro_rules! impl_via_from_dec_str {
-    ($ty: ty) => {
-        impl YamlDecode for $ty {
-            fn yaml_decode(string: &str) -> Result<Self, Error> {
-                Self::from_dec_str(string).map_err(|e| Error::FailedToParseTest(format!("{:?}", e)))
-            }
-        }
-    };
-}
-
-impl_via_from_dec_str!(U128);
-impl_via_from_dec_str!(U256);
-
-/// Types that already implement `serde::Deserialize` can be decoded using `serde_yaml`.
-macro_rules! impl_via_serde_yaml {
-    ($ty: ty) => {
-        impl YamlDecode for $ty {
-            fn yaml_decode(string: &str) -> Result<Self, Error> {
-                serde_yaml::from_str(string)
-                    .map_err(|e| Error::FailedToParseTest(format!("{:?}", e)))
-            }
-        }
-    };
-}
-
-impl_via_serde_yaml!(Fork);