diff --git a/exercises/practice/nucleotide-codons/tests/nucleotide_codons.rs b/exercises/practice/nucleotide-codons/tests/nucleotide_codons.rs
index bee25bb69..5263f7151 100644
--- a/exercises/practice/nucleotide-codons/tests/nucleotide_codons.rs
+++ b/exercises/practice/nucleotide-codons/tests/nucleotide_codons.rs
@@ -110,6 +110,6 @@ fn make_pairs() -> Vec<(&'static str, &'static str)> {
             pairs.push((codon, name));
         }
     }
-    pairs.sort_by(|&(_, a), &(_, b)| a.cmp(b));
+    pairs.sort_by_key(|&(_, name)| name);
     pairs
 }