Improve ef_tests crate

tests/ef_tests/src/lib.rs

@@ -1,4 +1,12 @@
+use error::Error;
 use serde_derive::Deserialize;
+use ssz::Decode;
+use std::fmt::Debug;
+use ethereum_types::{U256, U128};
+use test_decode::TestDecode;
+
+mod error;
+mod test_decode;
 
 #[derive(Debug, Deserialize)]
 pub struct TestDoc<T> {
@@ -21,6 +29,66 @@ pub struct SszGenericCase {
     pub ssz: Option<String>,
 }
 
+pub trait Test {
+    fn test(&self) -> Vec<Result<(), Error>>;
+}
+
+impl Test for TestDoc<SszGenericCase> {
+    fn test(&self) -> Vec<Result<(), Error>> {
+        self
+            .test_cases
+            .iter()
+            .map(|tc| {
+                if let Some(ssz) = &tc.ssz {
+                    match tc.type_name.as_ref() {
+                        "uint8" => compare_decoding::<u8>(tc.valid, ssz, &tc.value),
+                        "uint16" => compare_decoding::<u16>(tc.valid, ssz, &tc.value),
+                        "uint32" => compare_decoding::<u32>(tc.valid, ssz, &tc.value),
+                        "uint64" => compare_decoding::<u64>(tc.valid, ssz, &tc.value),
+                        "uint128" => compare_decoding::<U128>(tc.valid, ssz, &tc.value),
+                        "uint256" => compare_decoding::<U256>(tc.valid, ssz, &tc.value),
+                        _ => {
+                            Err(Error::FailedToParseTest(format!("Unknown type: {}", tc.type_name)))
+                        }
+                    }
+                } else {
+                    // Skip tests that do not have an ssz field.
+                    //
+                    // See: https://github.com/ethereum/eth2.0-specs/issues/1079
+                    Ok(())
+                }
+            })
+            .collect()
+    }
+}
+
+fn compare_decoding<T>(should_pass: bool, ssz: &String, value: &String) -> Result<(), Error>
+where
+    T: Decode + TestDecode + Debug + PartialEq<T>,
+{
+    let ssz = hex::decode(&ssz[2..])
+        .map_err(|e| Error::FailedToParseTest(format!("{:?}", e)))?;
+    let expected = T::test_decode(value)?;
+
+    let decoded = T::from_ssz_bytes(&ssz);
+
+    if should_pass {
+        let decoded = decoded.map_err(|e| Error::NotEqual(format!("{:?}", e)))?;
+
+        if decoded != expected {
+            Err(Error::NotEqual(format!("{:?} != {:?}", decoded, expected)))
+        } else {
+            Ok(())
+        }
+    } else {
+        if let Ok(decoded) = decoded {
+            Err(Error::DidntFail(format!("Decoded as {:?}", decoded)))
+        } else {
+            Ok(())
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     #[test]