Added unit tests for validation attributes generation

Author: Sergio0694

UnitTests/UnitTests.NetCore/Mvvm/Test_ObservablePropertyAttribute.cs

@@ -2,8 +2,12 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System;
 using System.Collections.Generic;
 using System.ComponentModel;
+using System.ComponentModel.DataAnnotations;
+using System.Configuration;
+using System.Reflection;
 using Microsoft.Toolkit.Mvvm.ComponentModel;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 
@@ -68,6 +72,50 @@ public void Test_AlsoNotifyForAttribute_Events()
             CollectionAssert.AreEqual(new[] { nameof(model.Name), nameof(model.FullName), nameof(model.Surname), nameof(model.FullName) }, propertyNames);
         }
 
+        [TestCategory("Mvvm")]
+        [TestMethod]
+        public void Test_ValidationAttributes()
+        {
+            var nameProperty = typeof(MyFormViewModel).GetProperty(nameof(MyFormViewModel.Name));
+
+            Assert.IsNotNull(nameProperty.GetCustomAttribute<RequiredAttribute>());
+            Assert.IsNotNull(nameProperty.GetCustomAttribute<MinLengthAttribute>());
+            Assert.AreEqual(nameProperty.GetCustomAttribute<MinLengthAttribute>().Length, 1);
+            Assert.IsNotNull(nameProperty.GetCustomAttribute<MaxLengthAttribute>());
+            Assert.AreEqual(nameProperty.GetCustomAttribute<MaxLengthAttribute>().Length, 100);
+
+            var ageProperty = typeof(MyFormViewModel).GetProperty(nameof(MyFormViewModel.Age));
+
+            Assert.IsNotNull(ageProperty.GetCustomAttribute<RangeAttribute>());
+            Assert.AreEqual(ageProperty.GetCustomAttribute<RangeAttribute>().Minimum, 0);
+            Assert.AreEqual(ageProperty.GetCustomAttribute<RangeAttribute>().Maximum, 120);
+
+            var emailProperty = typeof(MyFormViewModel).GetProperty(nameof(MyFormViewModel.Email));
+
+            Assert.IsNotNull(emailProperty.GetCustomAttribute<EmailAddressAttribute>());
+
+            var comboProperty = typeof(MyFormViewModel).GetProperty(nameof(MyFormViewModel.IfThisWorksThenThatsGreat));
+
+            TestValidationAttribute? testAttribute = comboProperty.GetCustomAttribute<TestValidationAttribute>();
+
+            Assert.IsNotNull(testAttribute);
+            Assert.IsNull(testAttribute.O);
+            Assert.AreEqual(testAttribute.T, typeof(SampleModel));
+            Assert.AreEqual(testAttribute.Flag, true);
+            Assert.AreEqual(testAttribute.D, 6.28);
+            CollectionAssert.AreEqual(testAttribute.Names, new[] { "Bob", "Ross" });
+
+            object[] nestedArray = (object[])testAttribute.NestedArray;
+
+            Assert.AreEqual(nestedArray.Length, 3);
+            Assert.AreEqual(nestedArray[0], 1);
+            Assert.AreEqual(nestedArray[1], "Hello");
+            Assert.IsTrue(nestedArray[2] is int[]);
+            CollectionAssert.AreEqual((int[])nestedArray[2], new[] { 2, 3, 4 });
+
+            Assert.AreEqual(testAttribute.Animal, Animal.Llama);
+        }
+
         public partial class SampleModel : ObservableObject
         {
             /// <summary>
@@ -90,5 +138,59 @@ public sealed partial class DependentPropertyModel
 
             public string FullName => $"{Name} {Surname}";
         }
+
+        public partial class MyFormViewModel : ObservableRecipient
+        {
+            [ObservableProperty]
+            [Required]
+            [MinLength(1)]
+            [MaxLength(100)]
+            private string name;
+
+            [ObservableProperty]
+            [Range(0, 120)]
+            private int age;
+
+            [ObservableProperty]
+            [EmailAddress]
+            private string email;
+
+            [ObservableProperty]
+            [TestValidation(null, typeof(SampleModel), true, 6.28, new[] { "Bob", "Ross" }, NestedArray = new object[] { 1, "Hello", new int[] { 2, 3, 4 } }, Animal = Animal.Llama)]
+            private int ifThisWorksThenThatsGreat;
+        }
+
+        private sealed class TestValidationAttribute : ValidationAttribute
+        {
+            public TestValidationAttribute(object o, Type t, bool flag, double d, string[] names)
+            {
+                O = o;
+                T = t;
+                Flag = flag;
+                D = d;
+                Names = names;
+            }
+
+            public object O { get; }
+
+            public Type T { get; }
+
+            public bool Flag { get; }
+
+            public double D { get; }
+
+            public string[] Names { get; }
+
+            public object NestedArray { get; set; }
+
+            public Animal Animal { get; set; }
+        }
+
+        public enum Animal
+        {
+            Cat,
+            Dog,
+            Llama
+        }
     }
 }