Update dedupe.test.js

Author: joanne342

Sprint-1/implement/dedupe.test.js

@@ -16,7 +16,6 @@ E.g. dedupe([1, 2, 1]) returns [1, 2]
 // Given an empty array
 // When passed to the dedupe function
 // Then it should return an empty array
-test.todo("given an empty array, it returns an empty array");
 
 // Given an array with no duplicates
 // When passed to the dedupe function