Work with Null property

phnx47 · Dec 18, 2019 · f2ff98b · f2ff98b
1 parent c24ff37
commit f2ff98b
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Showing 2 changed files with 22 additions and 1 deletion.
diff --git a/src/FingerprintBuilder.cs b/src/FingerprintBuilder.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 using System.Linq.Expressions;
 using System.Runtime.Serialization.Formatters.Binary;
 
@@ -61,7 +62,11 @@ public IFingerprintBuilder<T> For<TProperty>(Expression<Func<T, TProperty>> expr
                 using (var memory = new MemoryStream())
                 {
                     foreach (var item in _fingerprints)
-                        binaryFormatter.Serialize(memory, item.Value(obj));
+                    {
+                        var graph = item.Value(obj);
+                        if (graph != null)
+                            binaryFormatter.Serialize(memory, graph);
+                    }
 
                     return _computeHash(memory.ToArray());
                 }

diff --git a/tests/SimpleFingerprintBuilderTests.cs b/tests/SimpleFingerprintBuilderTests.cs
@@ -86,6 +86,22 @@ public void UserInfo_ToLowerCase_Sha256()
             var hash1 = fingerprint(user).ToLowerHexString();
             Assert.Equal(expectedHash, hash1);
         }
+
+        [Fact]
+        public void UserInfo_Sha1_Null()
+        {
+            var fingerprint = FingerprintBuilder<UserInfo>
+                .Create(SHA1.Create().ComputeHash)
+                .For(p => p.FirstName)
+                .For(p => p.LastName)
+                .Build();
+
+            var user = new UserInfo { FirstName = "John", LastName = null };
+
+            var hash = fingerprint(user).ToLowerHexString();
+
+            Assert.Equal("5ab5aeba11346413348fb7c9361058e016ecf3ca", hash);
+        }
 
         private class UserInfo
         {