test: fix decode tests

crates/eigenda/src/eigenda_data.rs

@@ -43,32 +43,48 @@ impl EigenDABlobData {
 
 #[cfg(test)]
 mod tests {
+    use crate::BLOB_ENCODING_VERSION_0;
+
     use super::*;
     use alloc::vec;
     use alloy_primitives::Bytes;
+    use kona_derive::errors::BlobDecodingError;
+
+    fn generate_blob_data(content: &[u8]) -> EigenDABlobData {
+        let mut blob = vec![0; 32];
+        blob[1] = BLOB_ENCODING_VERSION_0;
+        blob[2..6].copy_from_slice(&(content.len() as u32).to_be_bytes());
+        blob.extend_from_slice(&helpers::convert_by_padding_empty_byte(content));
+        EigenDABlobData {
+            blob: Bytes::from(blob),
+        }
+    }
 
     #[test]
     fn test_decode_success() {
-        let data = EigenDABlobData {
-            blob: Bytes::from(vec![1, 2, 3, 4]),
-        };
+        let content = vec![1, 2, 3, 4];
+        let data = generate_blob_data(&content);
         let result = data.decode();
         assert!(result.is_ok());
-        assert_eq!(result.unwrap(), Bytes::from(vec![1, 2, 3, 4]));
+        assert_eq!(result.unwrap(), Bytes::from(content));
     }
 
     #[test]
-    fn test_decode_empty_blob() {
-        let data = EigenDABlobData {
-            blob: Bytes::from(vec![]),
-        };
+    fn test_decode_success_empty() {
+        let content = vec![];
+        let data = generate_blob_data(&content);
         let result = data.decode();
         assert!(result.is_ok());
-        assert_eq!(result.unwrap(), Bytes::from(vec![]));
+        assert_eq!(result.unwrap(), Bytes::from(content));
     }
 
     #[test]
-    fn test_decode_invalid_blob() {
-        // TODO: implement this once decode actually does something
+    fn test_decode_error_invalid_length() {
+        let data = EigenDABlobData {
+            blob: Bytes::from(vec![0; 31]), // one byte short of having a full header
+        };
+        let result = data.decode();
+        assert!(result.is_err());
+        assert_eq!(result.unwrap_err(), BlobDecodingError::InvalidLength);
     }
 }