Select a specific constructor (#16)

Added support for picking a specific constructor for instantiation.
hhoangnl · Feb 18, 2022 · 31e9757 · 31e9757
1 parent b33b0c4
commit 31e9757
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Showing 4 changed files with 45 additions and 14 deletions.
diff --git a/FluentArrange.Tests/ArrangeTests.cs b/FluentArrange.Tests/ArrangeTests.cs
@@ -1,7 +1,7 @@
 // Copyright (c) Huy Hoang. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See LICENSE in the project root for license information.
 
-using System;
+using System.Linq;
 using FluentArrange.Tests.TestClasses;
 using FluentAssertions;
 using Xunit;
@@ -11,20 +11,30 @@ namespace FluentArrange.Tests
     public class ArrangeTests
     {
         [Fact]
-        public void For_MultipleCtorsFound_ShouldThrowInvalidOperationException()
+        public void For_MultipleCtorsFound_ShouldPickFirst()
         {
             // Act
-            Action act = () => Arrange.For<MultipleCtor>(type => new object());
+            var sut = Arrange.For<MultipleCtor>(_ => new object());
 
             // Assert
-            act.Should().Throw<InvalidOperationException>();
+            sut.Sut.CtorUsed.Should().Be(1);
+        }
+
+        [Fact]
+        public void For_PickSpecificCtor_ShouldUse()
+        {
+            // Act
+            var sut = Arrange.For<MultipleCtor>(_ => new Foo(), constructors => constructors.Last());
+
+            // Assert
+            sut.Sut.CtorUsed.Should().Be(2);
         }
 
         [Fact]
         public void For_ParameterlessCtor_ShouldNotHaveAnyDependencies()
         {
             // Act
-            var result = Arrange.For<AccountRepository>(type => new object());
+            var result = Arrange.For<AccountRepository>(_ => new object());
 
             // Assert
             result.Dependencies.Should().BeEmpty();
@@ -37,7 +47,7 @@ public void For_CtorWithParameters_ShouldReturnFluentArrangeObjectWithDependency
             var dependency = new AccountRepository();
 
             // Act
-            var result = Arrange.For<AccountService>(type => dependency);
+            var result = Arrange.For<AccountService>(_ => dependency);
 
             // Assert
             result.Dependencies.Values.Should().SatisfyRespectively(first => first.Should().Be(dependency));
@@ -50,7 +60,7 @@ public void Sut_Func_ShouldReturnDependency()
             var dependency = new AccountRepository();
 
             // Act
-            var result = Arrange.Sut<AccountService>(type => dependency);
+            var result = Arrange.Sut<AccountService>(_ => dependency);
 
             // Assert
             result.AccountRepository.Should().Be(dependency);
@@ -63,7 +73,7 @@ public void Sut_Func_Action_ShouldReturnDependency()
             var dependency = new AccountRepository();
 
             // Act
-            var result = Arrange.Sut<AccountService>(type => dependency, action => { });
+            var result = Arrange.Sut<AccountService>(_ => dependency, action => { });
 
             // Assert
             result.AccountRepository.Should().Be(dependency);
@@ -77,7 +87,7 @@ public void Sut_Func_Action_ShouldInvokeAction()
             var invoked = false;
 
             // Act
-            _ = Arrange.Sut<AccountService>(type => dependency, action => invoked = true);
+            _ = Arrange.Sut<AccountService>(_ => dependency, action => invoked = true);
 
             // Assert
             invoked.Should().BeTrue();

diff --git a/FluentArrange.Tests/TestClasses/MultipleCtor.cs b/FluentArrange.Tests/TestClasses/MultipleCtor.cs
@@ -5,12 +5,16 @@ namespace FluentArrange.Tests.TestClasses
 {
     public class MultipleCtor
     {
+        public int CtorUsed { get; }
+
         public MultipleCtor()
         {
+            CtorUsed = 1;
         }
 
         public MultipleCtor(IFoo foo)
         {
+            CtorUsed = 2;
         }
     }
 }
diff --git a/FluentArrange/Arrange.cs b/FluentArrange/Arrange.cs
@@ -10,17 +10,34 @@ namespace FluentArrange
 {
     public static class Arrange
     {
+        /// <summary>
+        /// Construct a class of type {T} (using the first public constructor) and inject it with mocked dependencies.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="createMockType"></param>
+        /// <returns></returns>
+        public static FluentArrangeContext<T> For<T>(Func<Type, object> createMockType)
+            where T : class
+        {
+            return For<T>(createMockType, constructors => constructors.FirstOrDefault(c => c.IsPublic));
+        }
+
         /// <summary>
         /// Construct a class of type {T} and inject it with mocked dependencies.
         /// </summary>
         /// <typeparam name="T">Type of the concrete class</typeparam>
         /// <param name="createMockType">The method to create mocked dependencies</param>
+        /// <param name="constructorSelector">Pick a specific constructor for instantiation</param>
         /// <returns>An instance of {T}</returns>
-        public static FluentArrangeContext<T> For<T>(Func<Type, object> createMockType)
+        public static FluentArrangeContext<T> For<T>(Func<Type, object> createMockType, Func<IEnumerable<ConstructorInfo>, ConstructorInfo?> constructorSelector)
             where T : class
         {
-            var constructor = typeof(T).GetTypeInfo().DeclaredConstructors.Single();
-
+            var constructor = constructorSelector.Invoke(typeof(T).GetTypeInfo().DeclaredConstructors);
+            if (constructor == null)
+            {
+                throw new InvalidOperationException("No matching constructor found.");
+            }
+
             var listOfDependencies = new Dictionary<Type, object>();
 
             foreach (var p in constructor.GetParameters())

diff --git a/FluentArrange/FluentArrange.csproj b/FluentArrange/FluentArrange.csproj
@@ -3,11 +3,11 @@
   <PropertyGroup>
     <TargetFramework>netstandard1.3</TargetFramework>
     <LangVersion>8.0</LangVersion>
-    <Version>0.10</Version>
+    <Version>0.11</Version>
     <Description>Write clean Arrange code using Fluent syntax.</Description>
     <PackageProjectUrl>https://github.com/hhoangnl/FluentArrange</PackageProjectUrl>
     <RepositoryUrl>https://github.com/hhoangnl/FluentArrange</RepositoryUrl>
-    <PackageReleaseNotes>Removed obsolete method</PackageReleaseNotes>
+    <PackageReleaseNotes>Added support for picking a specific constructor.</PackageReleaseNotes>
     <PackageTags>AAA TDD mocking unit-testing</PackageTags>
     <Authors>Huy Hoang</Authors>
     <Copyright>Huy Hoang</Copyright>