Added unit tests for create resource expressions

Author: Bart Koelman

src/JsonApiDotNetCore/Internal/IResourceFactory.cs

@@ -72,7 +72,7 @@ public NewExpression CreateNewExpression(Type resourceType)
                 try
                 {
                     object constructorArgument =
-                        ActivatorUtilities.CreateInstance(_serviceProvider, constructorParameter.ParameterType);
+                        ActivatorUtilities.GetServiceOrCreateInstance(_serviceProvider, constructorParameter.ParameterType);
 
                     constructorArguments.Add(Expression.Constant(constructorArgument));
                 }

test/UnitTests/Models/ResourceConstructionExpressionTests.cs

@@ -0,0 +1,76 @@
+using System;
+using System.ComponentModel.Design;
+using System.Linq.Expressions;
+using JsonApiDotNetCore.Internal;
+using JsonApiDotNetCoreExample.Data;
+using Microsoft.AspNetCore.Authentication;
+using Microsoft.EntityFrameworkCore;
+using Xunit;
+
+namespace UnitTests.Models
+{
+    public sealed class ResourceConstructionExpressionTests
+    {
+        [Fact]
+        public void When_resource_has_default_constructor_it_must_succeed()
+        {
+            // Arrange
+            var factory = new DefaultResourceFactory(new ServiceContainer());
+
+            // Act
+            NewExpression newExpression = factory.CreateNewExpression(typeof(ResourceWithoutConstructor));
+
+            // Assert
+            var function = Expression
+                .Lambda<Func<ResourceWithoutConstructor>>(newExpression)
+                .Compile();
+            
+            ResourceWithoutConstructor resource = function();
+            Assert.NotNull(resource);
+        }
+
+        [Fact]
+        public void When_resource_has_constructor_with_injectable_parameter_it_must_succeed()
+        {
+            // Arrange
+            var contextOptions = new DbContextOptionsBuilder<AppDbContext>().Options;
+            var systemClock = new FrozenSystemClock();
+            var appDbContext = new AppDbContext(contextOptions, systemClock);
+            
+            using var serviceContainer = new ServiceContainer();
+            serviceContainer.AddService(typeof(DbContextOptions<AppDbContext>), contextOptions);
+            serviceContainer.AddService(typeof(ISystemClock), systemClock);
+            serviceContainer.AddService(typeof(AppDbContext), appDbContext);
+
+            var factory = new DefaultResourceFactory(serviceContainer);
+
+            // Act
+            NewExpression newExpression = factory.CreateNewExpression(typeof(ResourceWithDbContextConstructor));
+
+            // Assert
+            var function = Expression
+                .Lambda<Func<ResourceWithDbContextConstructor>>(newExpression)
+                .Compile();
+
+            ResourceWithDbContextConstructor resource = function();
+            Assert.NotNull(resource);
+            Assert.Equal(appDbContext, resource.AppDbContext);
+        }
+
+        [Fact]
+        public void When_resource_has_constructor_with_string_parameter_it_must_fail()
+        {
+            // Arrange
+            var factory = new DefaultResourceFactory(new ServiceContainer());
+
+            // Act
+            Action action = () => factory.CreateNewExpression(typeof(ResourceWithStringConstructor));
+
+            // Assert
+            var exception = Assert.Throws<InvalidOperationException>(action);
+            Assert.Equal(
+                "Failed to create an instance of 'UnitTests.Models.ResourceWithStringConstructor': Parameter 'text' could not be resolved.",
+                exception.Message);
+        }
+    }
+}

test/UnitTests/Models/ResourceConstructionTests.cs

@@ -72,7 +72,7 @@ public void When_resource_has_default_constructor_that_throws_it_must_fail()
             // Assert
             var exception = Assert.Throws<InvalidOperationException>(action);
             Assert.Equal(
-                "Failed to create an instance of 'UnitTests.Models.ResourceConstructionTests+ResourceWithThrowingConstructor' using its default constructor.",
+                "Failed to create an instance of 'UnitTests.Models.ResourceWithThrowingConstructor' using its default constructor.",
                 exception.Message);
         }
 
@@ -138,40 +138,40 @@ public void When_resource_has_constructor_with_string_parameter_it_must_fail()
             // Assert
             var exception = Assert.Throws<InvalidOperationException>(action);
             Assert.Equal(
-                "Failed to create an instance of 'UnitTests.Models.ResourceConstructionTests+ResourceWithStringConstructor' using injected constructor parameters.",
+                "Failed to create an instance of 'UnitTests.Models.ResourceWithStringConstructor' using injected constructor parameters.",
                 exception.Message);
         }
+    }
 
-        public class ResourceWithoutConstructor : Identifiable
-        {
-        }
+    public class ResourceWithoutConstructor : Identifiable
+    {
+    }
 
-        public class ResourceWithDbContextConstructor : Identifiable
-        {
-            public AppDbContext AppDbContext { get; }
+    public class ResourceWithDbContextConstructor : Identifiable
+    {
+        public AppDbContext AppDbContext { get; }
 
-            public ResourceWithDbContextConstructor(AppDbContext appDbContext)
-            {
-                AppDbContext = appDbContext ?? throw new ArgumentNullException(nameof(appDbContext));
-            }
+        public ResourceWithDbContextConstructor(AppDbContext appDbContext)
+        {
+            AppDbContext = appDbContext ?? throw new ArgumentNullException(nameof(appDbContext));
         }
+    }
 
-        public class ResourceWithThrowingConstructor : Identifiable
+    public class ResourceWithThrowingConstructor : Identifiable
+    {
+        public ResourceWithThrowingConstructor()
         {
-            public ResourceWithThrowingConstructor()
-            {
-                throw new ArgumentException("Failed to initialize.");
-            }
+            throw new ArgumentException("Failed to initialize.");
         }
+    }
 
-        public class ResourceWithStringConstructor : Identifiable
-        {
-            public string Text { get; }
+    public class ResourceWithStringConstructor : Identifiable
+    {
+        public string Text { get; }
 
-            public ResourceWithStringConstructor(string text)
-            {
-                Text = text ?? throw new ArgumentNullException(nameof(text));
-            }
+        public ResourceWithStringConstructor(string text)
+        {
+            Text = text ?? throw new ArgumentNullException(nameof(text));
         }
     }
 }