Fix nullable reference types issue in HypermediaResponse (#2)

F23.Hateoas.Tests/HypermediaResponseTests.cs

@@ -0,0 +1,200 @@
+using System.Text.Json;
+
+namespace F23.Hateoas.Tests;
+
+public class HypermediaResponseTests
+{
+    [Fact]
+    public void Constructor_WithNonNullContent_ShouldSetContent()
+    {
+        // Arrange
+        var content = new { Name = "Test", Value = 42 };
+
+        // Act
+        var response = new HypermediaResponse(content);
+
+        // Assert
+        Assert.Equal(content, response.Content);
+    }
+
+    [Fact]
+    public void Constructor_WithNullContent_ShouldSetContentToNull()
+    {
+        // Arrange & Act
+        var response = new HypermediaResponse(null);
+
+        // Assert
+        Assert.Null(response.Content);
+    }
+
+    [Fact]
+    public void Constructor_WithStringContent_ShouldSetContent()
+    {
+        // Arrange
+        var content = "Hello, World!";
+
+        // Act
+        var response = new HypermediaResponse(content);
+
+        // Assert
+        Assert.Equal(content, response.Content);
+    }
+
+    [Fact]
+    public void Constructor_WithPrimitiveContent_ShouldSetContent()
+    {
+        // Arrange
+        var content = 123;
+
+        // Act
+        var response = new HypermediaResponse(content);
+
+        // Assert
+        Assert.Equal(content, response.Content);
+    }
+
+    [Fact]
+    public void Links_InitiallyNull_ShouldBeNull()
+    {
+        // Arrange & Act
+        var response = new HypermediaResponse("test");
+
+        // Assert
+        Assert.Null(response.Links);
+    }
+
+    [Fact]
+    public void Links_CanBeSetDirectly()
+    {
+        // Arrange
+        var response = new HypermediaResponse("test");
+        var links = new List<HypermediaLink>
+        {
+            new HypermediaLink("self", "/api/test")
+        };
+
+        // Act
+        response.Links = links;
+
+        // Assert
+        Assert.Equal(links, response.Links);
+        Assert.Single(response.Links);
+    }
+
+    [Fact]
+    public void Add_WithNullLinks_ShouldInitializeLinksAndAddLink()
+    {
+        // Arrange
+        var response = new HypermediaResponse("test");
+        var link = new HypermediaLink("self", "/api/test");
+
+        // Act
+        response.Add(link);
+
+        // Assert
+        Assert.NotNull(response.Links);
+        Assert.Single(response.Links);
+        Assert.Equal(link, response.Links[0]);
+    }
+
+    [Fact]
+    public void Add_WithExistingLinks_ShouldAppendLink()
+    {
+        // Arrange
+        var response = new HypermediaResponse("test");
+        var firstLink = new HypermediaLink("self", "/api/test");
+        var secondLink = new HypermediaLink("next", "/api/test/next");
+
+        // Act
+        response.Add(firstLink);
+        response.Add(secondLink);
+
+        // Assert
+        Assert.NotNull(response.Links);
+        Assert.Equal(2, response.Links.Count);
+        Assert.Equal(firstLink, response.Links[0]);
+        Assert.Equal(secondLink, response.Links[1]);
+    }
+
+    [Fact]
+    public void Add_MultipleLinks_ShouldMaintainOrder()
+    {
+        // Arrange
+        var response = new HypermediaResponse("test");
+        var links = new[]
+        {
+            new HypermediaLink("self", "/api/test"),
+            new HypermediaLink("edit", "/api/test/edit"),
+            new HypermediaLink("delete", "/api/test/delete")
+        };
+
+        // Act
+        foreach (var link in links)
+        {
+            response.Add(link);
+        }
+
+        // Assert
+        Assert.NotNull(response.Links);
+        Assert.Equal(3, response.Links.Count);
+        for (int i = 0; i < links.Length; i++)
+        {
+            Assert.Equal(links[i], response.Links[i]);
+        }
+    }
+
+    [Fact]
+    public void Serialize_WithNullContent_ShouldSerializeNull()
+    {
+        // Arrange
+        var response = new HypermediaResponse(null);
+
+        // Act
+        var json = JsonSerializer.Serialize(response);
+
+        // Assert
+        Assert.Equal("""{"content":null}""", json);
+    }
+
+    [Fact]
+    public void Serialize_WithNullContentAndLinks_ShouldSerializeNullContentAndIncludeLinks()
+    {
+        // Arrange
+        var response = new HypermediaResponse(null);
+        response.Add(new HypermediaLink("self", "/api/test"));
+
+        // Act
+        var json = JsonSerializer.Serialize(response);
+
+        // Assert
+        Assert.Equal("""{"content":null,"_links":[{"rel":"self","href":"/api/test"}]}""", json);
+    }
+
+    [Fact]
+    public void Serialize_WithComplexObjectContent_ShouldSerializeCorrectly()
+    {
+        // Arrange
+        var content = new { Id = 1, Name = "Test Item", Active = true };
+        var response = new HypermediaResponse(content);
+
+        // Act
+        var json = JsonSerializer.Serialize(response);
+
+        // Assert
+        Assert.Equal("""{"content":{"Id":1,"Name":"Test Item","Active":true}}""", json);
+    }
+
+    [Fact]
+    public void Serialize_WithArrayContent_ShouldSerializeCorrectly()
+    {
+        // Arrange
+        var content = new[] { 1, 2, 3 };
+        var response = new HypermediaResponse(content);
+
+        // Act
+        var json = JsonSerializer.Serialize(response);
+
+        // Assert
+        Assert.Equal("""{"content":[1,2,3]}""", json);
+    }
+}

F23.Hateoas/HypermediaResponse.cs

@@ -2,11 +2,11 @@
 
 namespace F23.Hateoas;
 
-public class HypermediaResponse(object content)
+public class HypermediaResponse(object? content)
 {
     [JsonPropertyName("content")]
     [JsonIgnore(Condition = JsonIgnoreCondition.Never)]
-    public object Content { get; } = content;
+    public object? Content { get; } = content;
 
     [JsonPropertyName("_links")]
     [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]