public void FindPrefix_PassedFStringArray_Returnsf()
 {
     string[] input = new string[] { "flower", "flow", "fello", "fleet" };
     Assert.AreEqual("f", LongestCommonPrefix.FindPrefix(input));
 }
 public void FindPrefix_PassedNoCommonPrefixStringArray_ReturnsEmptyString()
 {
     string[] input = new string[] { "abc", "def", "ghi" };
     Assert.AreEqual("", LongestCommonPrefix.FindPrefix(input));
 }