Support null and empty values (#412)

* Add support for null or empty values * Add additional test
ardalis · Aug 11, 2023 · 2d1bcc7 · 2d1bcc7
1 parent 3178f13
commit 2d1bcc7
Show file tree

Hide file tree

Showing 3 changed files with 40 additions and 13 deletions.
diff --git a/src/SmartEnum/SmartEnum.cs b/src/SmartEnum/SmartEnum.cs
@@ -1,4 +1,4 @@
-using System.Runtime.InteropServices.ComTypes;
+using System.Runtime.InteropServices.ComTypes;
 
 namespace Ardalis.SmartEnum
 {
@@ -55,7 +55,7 @@ public abstract class SmartEnum<TEnum, TValue> :
                 var dictionary = new Dictionary<TValue, TEnum>();
                 foreach (var item in _enumOptions.Value)
                 {
-                    if (!dictionary.ContainsKey(item._value))
+                    if (item._value != null && !dictionary.ContainsKey(item._value))
                         dictionary.Add(item._value, item);
                 }
                 return dictionary;
@@ -90,8 +90,6 @@ protected SmartEnum(string name, TValue value)
         {
             if (String.IsNullOrEmpty(name))
                 ThrowHelper.ThrowArgumentNullOrEmptyException(nameof(name));
-            if (value == null)
-                ThrowHelper.ThrowArgumentNullException(nameof(value));
 
             _name = name;
             _value = value;
@@ -203,12 +201,22 @@ public static bool TryFromName(string name, bool ignoreCase, out TEnum result)
         /// <seealso cref="SmartEnum{TEnum, TValue}.TryFromValue(TValue, out TEnum)"/>
         public static TEnum FromValue(TValue value)
         {
-            if (value == null)
-                ThrowHelper.ThrowArgumentNullException(nameof(value));
+            TEnum result;
 
-            if (!_fromValue.Value.TryGetValue(value, out var result))
+            if (value != null)
+            {
+                if (!_fromValue.Value.TryGetValue(value, out result))
+                {
+                    ThrowHelper.ThrowValueNotFoundException<TEnum, TValue>(value);
+                }
+            }
+            else
             {
-                ThrowHelper.ThrowValueNotFoundException<TEnum, TValue>(value);
+                result = _enumOptions.Value.FirstOrDefault(x => x.Value == null);
+                if (result == null)
+                {
+                    ThrowHelper.ThrowValueNotFoundException<TEnum, TValue>(value);
+                }
             }
             return result;
         }

diff --git a/test/SmartEnum.UnitTests/SmartEnumStringFromValue.cs b/test/SmartEnum.UnitTests/SmartEnumStringFromValue.cs
@@ -1,4 +1,4 @@
-namespace Ardalis.SmartEnum.UnitTests
+namespace Ardalis.SmartEnum.UnitTests
 {
     using FluentAssertions;
     using System;
@@ -23,10 +23,18 @@ public void ReturnsEnumGivenMatchingValue(string value, TestStringEnum expected)
         }
 
         [Fact]
-        public void ThrowsGivenNonMatchingValue()
+        public void ReturnsEnumGivenMatchingNullValue()
         {
-            var value = string.Empty;
+            var result = TestNullableStringEnum.FromValue(null);
 
+            result.Should().BeSameAs(TestNullableStringEnum.None);
+        }
+
+        [Theory]
+        [InlineData("invalid")]
+        [InlineData(null)]
+        public void ThrowsGivenNonMatchingValue(string value)
+        {
             Action action = () => TestStringEnum.FromValue(value);
 
             action.Should()
@@ -38,14 +46,15 @@ public void ThrowsGivenNonMatchingValue()
         [Fact]
         public void ReturnsDefaultEnumGivenNonMatchingValue()
         {
-            var value = string.Empty;
+            var value = "invalid";
             var defaultEnum = TestStringEnum.One;
 
             var result = TestStringEnum.FromValue(value, defaultEnum);
 
             result.Should().BeSameAs(defaultEnum);
         }
 
+
         [Fact]
         public void ReturnsDerivedEnumByValue()
         {

diff --git a/test/SmartEnum.UnitTests/TestEnum.cs b/test/SmartEnum.UnitTests/TestEnum.cs
@@ -1,4 +1,4 @@
-using System.Runtime.CompilerServices;
+using System.Runtime.CompilerServices;
 
 namespace Ardalis.SmartEnum.UnitTests
 {
@@ -46,12 +46,22 @@ public class TestStringEnum : SmartEnum<TestStringEnum, string>
         public static readonly TestStringEnum One = new TestStringEnum(nameof(One), nameof(One));
         public static readonly TestStringEnum Two = new TestStringEnum(nameof(Two), nameof(Two));
         public static readonly TestStringEnum Three = new TestStringEnum(nameof(Three), nameof(Three));
+        public static readonly TestStringEnum Empty = new TestStringEnum(nameof(Empty), string.Empty);
 
         protected TestStringEnum(string name, string value) : base(name, value)
         {
         }
     }
 
+    public class TestNullableStringEnum : SmartEnum<TestNullableStringEnum, string>
+    {
+        public static readonly TestNullableStringEnum None = new TestNullableStringEnum(nameof(None), null);
+
+        protected TestNullableStringEnum(string name, string value) : base(name, value)
+        {
+        }
+    }
+
     public class TestBaseEnumWithDerivedValues : SmartEnum<TestBaseEnumWithDerivedValues>
     {
         protected TestBaseEnumWithDerivedValues(string name, int value) : base(name, value)