diff --git a/src/test_data.rs b/src/test_data.rs
index 1d9119d..15cee34 100644
--- a/src/test_data.rs
+++ b/src/test_data.rs
@@ -13,33 +13,34 @@ pub fn segmenter() -> Segmenter {
     let uni_file = dir.join("unigrams.txt");
     let reader = BufReader::new(File::open(&uni_file).unwrap());
     let unigrams = reader.lines().enumerate().map(move |(i, ln)| {
-        let ln = ln.expect(&format!("line error at {:?}:{}", uni_file, i));
+        let ln = ln.unwrap_or_else(|e| panic!("line error at {:?}:{}: {}", uni_file, i, e));
         let split = ln
             .find('\t')
-            .expect(&format!("no tab found in {:?}:{}", uni_file, i));
+            .unwrap_or_else(|| panic!("no tab found in {:?}:{}", uni_file, i));
 
         let word = ln[..split].into();
-        let p = usize::from_str(&ln[split + 1..]).expect(&format!("error at {:?}:{}", uni_file, i));
+        let p = usize::from_str(&ln[split + 1..])
+            .unwrap_or_else(|e| panic!("error at {:?}:{}: {}", uni_file, i, e));
         (word, p as f64)
     });
 
     let bi_file = dir.join("bigrams.txt");
     let reader = BufReader::new(File::open(&bi_file).unwrap());
     let bigrams = reader.lines().enumerate().map(move |(i, ln)| {
-        let ln = ln.expect(&format!("line error at {:?}:{}", bi_file, i));
+        let ln = ln.unwrap_or_else(|e| panic!("line error at {:?}:{}: {}", bi_file, i, e));
         let word_split = ln
             .find(' ')
-            .expect(&format!("no space found in {:?}:{}", bi_file, i));
+            .unwrap_or_else(|| panic!("no space found in {:?}:{}", bi_file, i));
         let score_split = ln[word_split + 1..]
             .find('\t')
-            .expect(&format!("no tab found in {:?}:{}", bi_file, i))
+            .unwrap_or_else(|| panic!("no tab found in {:?}:{}", bi_file, i))
             + word_split
             + 1;
 
         let word1 = ln[..word_split].into();
         let word2 = ln[word_split + 1..score_split].into();
         let p = usize::from_str(&ln[score_split + 1..])
-            .expect(&format!("error at {:?}:{}", bi_file, i));
+            .unwrap_or_else(|e| panic!("error at {:?}:{}: {}", bi_file, i, e));
 
         ((word1, word2), p as f64)
     });