Fuzz test for u8 fails

eth2/utils/ssz/fuzz/Cargo.toml

@@ -20,3 +20,7 @@ members = ["."]
 [[bin]]
 name = "fuzz_target_u8"
 path = "fuzz_targets/fuzz_target_u8.rs"
+
+[[bin]]
+name = "fuzz_target_u16"
+path = "fuzz_targets/fuzz_target_u16.rs"

eth2/utils/ssz/fuzz/fuzz_targets/fuzz_target_u16.rs

@@ -0,0 +1,19 @@
+#![no_main]
+#[macro_use] extern crate libfuzzer_sys;
+extern crate ssz;
+
+use ssz::{DecodeError, Decodable, Encodable};
+
+// Fuzz ssz_decode(u8)
+fuzz_target!(|data: &[u8]| {
+    let result: Result<(u16, usize), DecodeError> = Decodable::ssz_decode(data, 0);
+    if data.len() > 1 {
+        // Valid result
+        let (number_u16, index) = result.unwrap();
+        assert_eq!(index, 2);
+        // TODO: add test for number?
+    } else {
+        // Length of 0 or 1 should return error
+        assert_eq!(result, Err(DecodeError::TooShort));
+    }
+});

eth2/utils/ssz/fuzz/fuzz_targets/fuzz_target_u8.rs

@@ -7,4 +7,13 @@ use ssz::{DecodeError, Decodable, Encodable};
 // Fuzz ssz_decode(u8)
 fuzz_target!(|data: &[u8]| {
     let result: Result<(u8, usize), DecodeError> = Decodable::ssz_decode(data, 0);
+    if data.len() > 0 {
+        // Should have valid result
+        let (number_u8, index) = result.unwrap();
+        assert_eq!(number_u8, data[0]);
+        assert_eq!(index, 2);
+    } else {
+        // Length of 0 should return error
+        assert_eq!(result, Err(DecodeError::TooShort));
+    }
 });