patch #194

Author: ymh199478

src/CatLib.Core.Tests/Support/Util/StrTests.cs

@@ -368,6 +368,12 @@ public void TestLevenshteinLargeThan255()
             Assert.AreEqual(-1, Str.Levenshtein(builder.ToString(), "world"));
         }
 
+        [TestMethod]
+        public void TestLevenshteinNull()
+        {
+            Assert.AreEqual(-1, Str.Levenshtein(null, "1"));
+        }
+
         [TestMethod]
         public void TestJoinList()
         {

src/CatLib.Core/Support/Util/Str.cs

@@ -503,6 +503,11 @@ public static string Truncate(string str, int length, object separator = null, s
         /// </returns>
         public static int Levenshtein(string str1, string str2)
         {
+            if (str1 == null || str2 == null)
+            {
+                return -1;
+            }
+
             var length1 = str1.Length;
             var length2 = str2.Length;