From 725a3ed790d521d44cbd1951216db8aa09b5787f Mon Sep 17 00:00:00 2001
From: "Dominik.Kotecki" <dominikus1910@gmail.com>
Date: Sat, 11 May 2024 17:16:02 +0200
Subject: [PATCH] add unit tests

---
 src/Modules/Basket/Core/Dtos/Dto.cs           |  4 +-
 src/Modules/Basket/Core/Model/Products.cs     |  5 +-
 .../Basket.Tests/Core/Model/ProductsTests.cs  | 62 +++++++++++++++++++
 3 files changed, 67 insertions(+), 4 deletions(-)

diff --git a/src/Modules/Basket/Core/Dtos/Dto.cs b/src/Modules/Basket/Core/Dtos/Dto.cs
index d5a8caa..7bef129 100644
--- a/src/Modules/Basket/Core/Dtos/Dto.cs
+++ b/src/Modules/Basket/Core/Dtos/Dto.cs
@@ -26,7 +26,7 @@ public BasketItemDto(Product item)
 public sealed class CustomerBasketDto
 {
     public required CustomerId CustomerId { get; init; }
-    public required IReadOnlyCollection<BasketItemDto> Items { get; init; }
+    public required IReadOnlyList<BasketItemDto> Items { get; init; }
     
     public CustomerBasketDto()
     {
@@ -37,6 +37,6 @@ public CustomerBasketDto()
     public CustomerBasketDto(CustomerBasket basket)
     {
         CustomerId = basket.CustomerId;
-        Items = basket.Products.MapItems(item => new BasketItemDto(item)).ToArray();
+        Items = basket.Products.MapItems(item => new BasketItemDto(item));
     }
 }
\ No newline at end of file
diff --git a/src/Modules/Basket/Core/Model/Products.cs b/src/Modules/Basket/Core/Model/Products.cs
index ae5a3a3..ab0e032 100644
--- a/src/Modules/Basket/Core/Model/Products.cs
+++ b/src/Modules/Basket/Core/Model/Products.cs
@@ -19,6 +19,7 @@ private Products(IReadOnlyList<Product> items)
     public static readonly Products Empty = new([]);
     public Products AddItem(Product item)
     {
+        ArgumentNullException.ThrowIfNull(item);
         var items = new List<Product>(_items);
         var index = items.IndexOf(item);
         if (index == -1)
@@ -71,9 +72,9 @@ public IReadOnlyList<T> MapItems<T>(Func<Product, T> map)
         switch (_items)
         {
             case null or {Count: 0}:
-                return Array.Empty<T>();
+                return [];
             case [var element]:
-                return new[] { map(element) };
+                return [map(element)];
         }
 
         var array = new T[_items.Count];
diff --git a/tests/Modules/Basket.Tests/Core/Model/ProductsTests.cs b/tests/Modules/Basket.Tests/Core/Model/ProductsTests.cs
index 1c5e9e2..82fe093 100644
--- a/tests/Modules/Basket.Tests/Core/Model/ProductsTests.cs
+++ b/tests/Modules/Basket.Tests/Core/Model/ProductsTests.cs
@@ -24,4 +24,66 @@ public void CollectionInitializerWhenNoEmptyTests(Product product)
         Assert.False(subject.IsEmpty);
         Assert.Single(subject);
     }
+    
+    [Theory]
+    [AutoData]
+    public void AddItemTests(Product product)
+    {
+        Products subject = [];
+        
+        var result = subject.AddItem(product);
+        
+        Assert.Single(result);
+        Assert.Contains(result, x => x == product);
+    }
+    
+    [Fact]
+    public void AddNullItemTests()
+    {
+        Products subject = [];
+        
+        Assert.Throws<ArgumentNullException>(() => subject.AddItem(null!));
+    }
+    
+    
+    [Theory]
+    [AutoData]
+    public void MapOneItemItemsTests(Product product)
+    {
+        Products subject = [];
+        
+        var result = subject.AddItem(product);
+        
+        Assert.Single(result);
+        
+        var mapped = result.MapItems(x => x.Quantity);
+        
+        Assert.Single(mapped);
+    }
+    
+    [Fact]
+    public void MapEmptyItemsTests()
+    {
+        Products subject = [];
+        
+        var mapped = subject.MapItems(x => x.Quantity);
+        
+        Assert.Empty(mapped);
+    }
+    
+    [Theory]
+    [AutoData]
+    public void MapItemsTests(Product[] products)
+    {
+        Products subject = [];
+
+        foreach (var p in products)
+        {
+            subject = subject.AddItem(p);
+        }
+        
+        var mapped = subject.MapItems(x => x.Quantity);
+        
+        Assert.Equal(products.Length, mapped.Count);
+    }
 }
\ No newline at end of file