Added setup method to instantiate clean builder for all model unit tests within the class.

src/Umbraco.Tests.UnitTests/Umbraco.Infrastructure/Models/DataTypeTests.cs

@@ -9,7 +9,13 @@ namespace Umbraco.Tests.UnitTests.Umbraco.Infrastructure.Models
     [TestFixture]
     public class DataTypeTests
     {
-        private readonly DataTypeBuilder _builder = new DataTypeBuilder();
+        private DataTypeBuilder _builder;
+
+        [SetUp]
+        public void SetUp()
+        {
+            _builder = new DataTypeBuilder();
+        }
 
         [Test]
         public void Can_Deep_Clone()

src/Umbraco.Tests.UnitTests/Umbraco.Infrastructure/Models/DictionaryItemTests.cs

@@ -9,7 +9,13 @@ namespace Umbraco.Tests.UnitTests.Umbraco.Infrastructure.Models
     [TestFixture]
     public class DictionaryItemTests
     {
-        private readonly DictionaryItemBuilder _builder = new DictionaryItemBuilder();
+        private DictionaryItemBuilder _builder = new DictionaryItemBuilder();
+
+        [SetUp]
+        public void SetUp()
+        {
+            _builder = new DictionaryItemBuilder();
+        }
 
         [Test]
         public void Can_Deep_Clone()

src/Umbraco.Tests.UnitTests/Umbraco.Infrastructure/Models/LanguageTests.cs

@@ -8,7 +8,13 @@ namespace Umbraco.Tests.UnitTests.Umbraco.Infrastructure.Models
     [TestFixture]
     public class LanguageTests
     {
-        private readonly LanguageBuilder _builder = new LanguageBuilder();
+        private LanguageBuilder _builder = new LanguageBuilder();
+
+        [SetUp]
+        public void SetUp()
+        {
+            _builder = new LanguageBuilder();
+        }
 
         [Test]
         public void Can_Deep_Clone()

src/Umbraco.Tests.UnitTests/Umbraco.Infrastructure/Models/MacroTests.cs

@@ -11,7 +11,13 @@ namespace Umbraco.Tests.UnitTests.Umbraco.Infrastructure.Models
     [TestFixture]
     public class MacroTests
     {
-        private readonly MacroBuilder _builder = new MacroBuilder();
+        private MacroBuilder _builder;
+
+        [SetUp]
+        public void SetUp()
+        {
+            _builder = new MacroBuilder();
+        }
 
         [Test]
         public void Can_Deep_Clone()

src/Umbraco.Tests.UnitTests/Umbraco.Infrastructure/Models/MemberGroupTests.cs

@@ -11,7 +11,13 @@ namespace Umbraco.Tests.UnitTests.Umbraco.Infrastructure.Models
     [TestFixture]
     public class MemberGroupTests
     {
-        private readonly MemberGroupBuilder _builder = new MemberGroupBuilder();
+        private MemberGroupBuilder _builder;
+
+        [SetUp]
+        public void SetUp()
+        {
+            _builder = new MemberGroupBuilder();
+        }
 
         [Test]
         public void Can_Deep_Clone()

src/Umbraco.Tests.UnitTests/Umbraco.Infrastructure/Models/MemberTests.cs

@@ -13,7 +13,13 @@ namespace Umbraco.Tests.UnitTests.Umbraco.Infrastructure.Models
     [TestFixture]
     public class MemberTests
     {
-        private readonly MemberBuilder _builder = new MemberBuilder();
+        private MemberBuilder _builder;
+
+        [SetUp]
+        public void SetUp()
+        {
+            _builder = new MemberBuilder();
+        }
 
         [Test]
         public void Can_Deep_Clone()

src/Umbraco.Tests.UnitTests/Umbraco.Infrastructure/Models/PathValidationTests.cs

@@ -12,7 +12,13 @@ namespace Umbraco.Tests.UnitTests.Umbraco.Infrastructure.Models
     [TestFixture]
     public class PathValidationTests
     {
-        private EntitySlimBuilder _builder = new EntitySlimBuilder();
+        private EntitySlimBuilder _builder;
+
+        [SetUp]
+        public void SetUp()
+        {
+            _builder = new EntitySlimBuilder();
+        }
 
         [Test]
         public void Validate_Path()
@@ -93,12 +99,11 @@ namespace Umbraco.Tests.UnitTests.Umbraco.Infrastructure.Models
         [Test]
         public void Ensure_Path_Entity_Valid_Recursive_Parent()
         {
-            // Re-creating the class-level builder as we need to reset before usage when creating multiple entities.
-            _builder = new EntitySlimBuilder();
             var parentA = _builder
                 .WithId(999)
                 .Build();
 
+            // Re-creating the class-level builder as we need to reset before usage when creating multiple entities.
             _builder = new EntitySlimBuilder();
             var parentB = _builder
                 .WithId(888)

src/Umbraco.Tests.UnitTests/Umbraco.Infrastructure/Models/PropertyGroupTests.cs

@@ -11,7 +11,13 @@ namespace Umbraco.Tests.UnitTests.Umbraco.Infrastructure.Models
     [TestFixture]
     public class PropertyGroupTests
     {
-        private readonly PropertyGroupBuilder _builder = new PropertyGroupBuilder();
+        private PropertyGroupBuilder _builder;
+
+        [SetUp]
+        public void SetUp()
+        {
+            _builder = new PropertyGroupBuilder();
+        }
 
         [Test]
         public void Can_Deep_Clone()

src/Umbraco.Tests.UnitTests/Umbraco.Infrastructure/Models/PropertyTests.cs

@@ -10,7 +10,13 @@ namespace Umbraco.Tests.UnitTests.Umbraco.Infrastructure.Models
     [TestFixture]
     public class PropertyTests
     {
-        private readonly PropertyBuilder _builder = new PropertyBuilder();
+        private PropertyBuilder _builder;
+
+        [SetUp]
+        public void SetUp()
+        {
+            _builder = new PropertyBuilder();
+        }
 
         [Test]
         public void Can_Deep_Clone()

src/Umbraco.Tests.UnitTests/Umbraco.Infrastructure/Models/PropertyTypeTests.cs

@@ -13,7 +13,13 @@ namespace Umbraco.Tests.UnitTests.Umbraco.Infrastructure.Models
     [TestFixture]
     public class PropertyTypeTests
     {
-        private readonly PropertyTypeBuilder _builder = new PropertyTypeBuilder();
+        private PropertyTypeBuilder _builder;
+
+        [SetUp]
+        public void SetUp()
+        {
+            _builder = new PropertyTypeBuilder();
+        }
 
         [Test]
         public void Can_Deep_Clone()

src/Umbraco.Tests.UnitTests/Umbraco.Infrastructure/Models/RelationTests.cs

@@ -11,7 +11,13 @@ namespace Umbraco.Tests.UnitTests.Umbraco.Infrastructure.Models
     [TestFixture]
     public class RelationTests
     {
-        private readonly RelationBuilder _builder = new RelationBuilder();
+        private RelationBuilder _builder;
+
+        [SetUp]
+        public void SetUp()
+        {
+            _builder = new RelationBuilder();
+        }
 
         [Test]
         public void Can_Deep_Clone()

src/Umbraco.Tests.UnitTests/Umbraco.Infrastructure/Models/RelationTypeTests.cs

@@ -9,7 +9,13 @@ namespace Umbraco.Tests.UnitTests.Umbraco.Infrastructure.Models
     [TestFixture]
     public class RelationTypeTests
     {
-        private readonly RelationTypeBuilder _builder = new RelationTypeBuilder();
+        private RelationTypeBuilder _builder;
+
+        [SetUp]
+        public void SetUp()
+        {
+            _builder = new RelationTypeBuilder();
+        }
 
         [Test]
         public void Can_Deep_Clone()

src/Umbraco.Tests.UnitTests/Umbraco.Infrastructure/Models/StylesheetTests.cs

@@ -10,7 +10,13 @@ namespace Umbraco.Tests.UnitTests.Umbraco.Infrastructure.Models
     [TestFixture]
     public class StylesheetTests
     {
-        private readonly StylesheetBuilder _builder = new StylesheetBuilder();
+        private StylesheetBuilder _builder;
+
+        [SetUp]
+        public void SetUp()
+        {
+            _builder = new StylesheetBuilder();
+        }
 
         [Test]
         public void Can_Create_Stylesheet()

src/Umbraco.Tests.UnitTests/Umbraco.Infrastructure/Models/TemplateTests.cs

@@ -6,7 +6,6 @@ using Newtonsoft.Json;
 using NUnit.Framework;
 using Umbraco.Core.Models;
 using Umbraco.Tests.Common.Builders;
-
 using Umbraco.Tests.Common.Builders.Extensions;
 
 namespace Umbraco.Tests.UnitTests.Umbraco.Infrastructure.Models
@@ -14,7 +13,13 @@ namespace Umbraco.Tests.UnitTests.Umbraco.Infrastructure.Models
     [TestFixture]
     public class TemplateTests
     {
-        private readonly TemplateBuilder _builder = new TemplateBuilder();
+        private TemplateBuilder _builder;
+
+        [SetUp]
+        public void SetUp()
+        {
+            _builder = new TemplateBuilder();
+        }
 
         [Test]
         public void Can_Deep_Clone()

src/Umbraco.Tests.UnitTests/Umbraco.Infrastructure/Models/UserExtensionsTests.cs

@@ -13,7 +13,13 @@ namespace Umbraco.Tests.UnitTests.Umbraco.Infrastructure.Models
     [TestFixture]
     public class UserExtensionsTests
     {
-        private readonly UserBuilder _userBuilder = new UserBuilder();
+        private UserBuilder _userBuilder;
+
+        [SetUp]
+        public void SetUp()
+        {
+            _userBuilder = new UserBuilder();
+        }
 
         [TestCase(-1, "-1", "-1,1,2,3,4,5", true)] // below root start node
         [TestCase(2, "-1,1,2", "-1,1,2,3,4,5", true)] // below start node

src/Umbraco.Tests.UnitTests/Umbraco.Infrastructure/Models/UserTests.cs

@@ -12,7 +12,13 @@ namespace Umbraco.Tests.UnitTests.Umbraco.Infrastructure.Models
     [TestFixture]
     public class UserTests
     {
-        private readonly UserBuilder _builder = new UserBuilder();
+        private UserBuilder _builder;
+
+        [SetUp]
+        public void SetUp()
+        {
+            _builder = new UserBuilder();
+        }
 
         [Test]
         public void Can_Deep_Clone()