Add additional constructors for json serialization and add JsonConstructor attributes

src/ImageSharp/Formats/Webp/Lossy/Vp8BandProbas.cs

@@ -1,6 +1,8 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using System.Text.Json.Serialization;
+
 namespace SixLabors.ImageSharp.Formats.Webp.Lossy;
 
 /// <summary>
@@ -20,6 +22,13 @@ internal class Vp8BandProbas
         }
     }
 
+    /// <summary>
+    /// Initializes a new instance of the <see cref="Vp8BandProbas"/> class.
+    /// Only used for unit tests.
+    /// </summary>
+    [JsonConstructor]
+    public Vp8BandProbas(Vp8ProbaArray[] probabilities) => this.Probabilities = probabilities;
+
     /// <summary>
     /// Gets the Probabilities.
     /// </summary>

src/ImageSharp/Formats/Webp/Lossy/Vp8CostArray.cs

@@ -1,6 +1,8 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using System.Text.Json.Serialization;
+
 namespace SixLabors.ImageSharp.Formats.Webp.Lossy;
 
 internal class Vp8CostArray
@@ -10,5 +12,12 @@ internal class Vp8CostArray
     /// </summary>
     public Vp8CostArray() => this.Costs = new ushort[67 + 1];
 
+    /// <summary>
+    /// Initializes a new instance of the <see cref="Vp8CostArray"/> class.
+    /// Only used for unit tests.
+    /// </summary>
+    [JsonConstructor]
+    public Vp8CostArray(ushort[] costs) => this.Costs = costs;
+
     public ushort[] Costs { get; }
 }

src/ImageSharp/Formats/Webp/Lossy/Vp8Costs.cs

@@ -1,6 +1,8 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using System.Text.Json.Serialization;
+
 namespace SixLabors.ImageSharp.Formats.Webp.Lossy;
 
 internal class Vp8Costs
@@ -17,6 +19,13 @@ internal class Vp8Costs
         }
     }
 
+    /// <summary>
+    /// Initializes a new instance of the <see cref="Vp8Costs"/> class.
+    /// Only used for unit tests.
+    /// </summary>
+    [JsonConstructor]
+    public Vp8Costs(Vp8CostArray[] costs) => this.Costs = costs;
+
     /// <summary>
     /// Gets the Costs.
     /// </summary>

src/ImageSharp/Formats/Webp/Lossy/Vp8ProbaArray.cs

@@ -1,6 +1,8 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using System.Text.Json.Serialization;
+
 namespace SixLabors.ImageSharp.Formats.Webp.Lossy;
 
 /// <summary>
@@ -13,6 +15,13 @@ internal class Vp8ProbaArray
     /// </summary>
     public Vp8ProbaArray() => this.Probabilities = new byte[WebpConstants.NumProbas];
 
+    /// <summary>
+    /// Initializes a new instance of the <see cref="Vp8ProbaArray"/> class.
+    /// Only used for unit tests.
+    /// </summary>
+    [JsonConstructor]
+    public Vp8ProbaArray(byte[] probabilities) => this.Probabilities = probabilities;
+
     /// <summary>
     /// Gets the probabilities.
     /// </summary>

src/ImageSharp/Formats/Webp/Lossy/Vp8Residual.cs

@@ -7,6 +7,7 @@ using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using System.Runtime.Intrinsics;
 using System.Runtime.Intrinsics.X86;
+using System.Text.Json.Serialization;
 
 namespace SixLabors.ImageSharp.Formats.Webp.Lossy;
 
@@ -15,6 +16,22 @@ namespace SixLabors.ImageSharp.Formats.Webp.Lossy;
 /// </summary>
 internal class Vp8Residual
 {
+    public Vp8Residual()
+    {
+    }
+
+    [JsonConstructor]
+    public Vp8Residual(int first, int last, int coeffType, short[] coeffs, Vp8BandProbas[] prob, Vp8Stats[] stats, Vp8Costs[] costs)
+    {
+        this.First = first;
+        this.Last = last;
+        this.CoeffType = coeffType;
+        this.Coeffs = coeffs;
+        this.Prob = prob;
+        this.Stats = stats;
+        this.Costs = costs;
+    }
+
     public int First { get; set; }
 
     public int Last { get; set; }

src/ImageSharp/Formats/Webp/Lossy/Vp8Stats.cs

@@ -1,6 +1,8 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using System.Text.Json.Serialization;
+
 namespace SixLabors.ImageSharp.Formats.Webp.Lossy;
 
 internal class Vp8Stats
@@ -17,5 +19,12 @@ internal class Vp8Stats
         }
     }
 
+    /// <summary>
+    /// Initializes a new instance of the <see cref="Vp8Stats"/> class.
+    /// Only used for unit tests.
+    /// </summary>
+    [JsonConstructor]
+    public Vp8Stats(Vp8StatsArray[] stats) => this.Stats = stats;
+
     public Vp8StatsArray[] Stats { get; }
 }

src/ImageSharp/Formats/Webp/Lossy/Vp8StatsArray.cs

@@ -1,6 +1,8 @@
 // Copyright (c) Six Labors.
 // Licensed under the Six Labors Split License.
 
+using System.Text.Json.Serialization;
+
 namespace SixLabors.ImageSharp.Formats.Webp.Lossy;
 
 internal class Vp8StatsArray
@@ -10,5 +12,12 @@ internal class Vp8StatsArray
     /// </summary>
     public Vp8StatsArray() => this.Stats = new uint[WebpConstants.NumProbas];
 
+    /// <summary>
+    /// Initializes a new instance of the <see cref="Vp8StatsArray"/> class.
+    /// Only used for unit tests.
+    /// </summary>
+    [JsonConstructor]
+    public Vp8StatsArray(uint[] stats) => this.Stats = stats;
+
     public uint[] Stats { get; }
 }

tests/ImageSharp.Tests/Formats/WebP/Serialization/Vp8CostArrayJsonConverter.cs

@@ -1,15 +0,0 @@
-// Copyright (c) Six Labors.
-// Licensed under the Six Labors Split License.
-
-using System.Text.Json;
-using System.Text.Json.Serialization;
-using SixLabors.ImageSharp.Formats.Webp.Lossy;
-
-namespace SixLabors.ImageSharp.Tests.Formats.WebP.Serialization;
-
-internal class Vp8CostArrayJsonConverter : JsonConverter<Vp8CostArray>
-{
-    public override Vp8CostArray Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options) => throw new NotImplementedException();
-
-    public override void Write(Utf8JsonWriter writer, Vp8CostArray value, JsonSerializerOptions options) => throw new NotImplementedException();
-}

tests/ImageSharp.Tests/Formats/WebP/Vp8ResidualTests.cs

@@ -2,10 +2,8 @@
 // Licensed under the Six Labors Split License.
 
 using System.Runtime.Intrinsics.X86;
-using System.Text.Json;
 using SixLabors.ImageSharp.Formats.Webp;
 using SixLabors.ImageSharp.Formats.Webp.Lossy;
-using SixLabors.ImageSharp.Tests.Formats.WebP.Serialization;
 using SixLabors.ImageSharp.Tests.TestUtilities;
 using JsonSerializer = System.Text.Json.JsonSerializer;
 
@@ -14,29 +12,6 @@ namespace SixLabors.ImageSharp.Tests.Formats.Webp;
 [Trait("Format", "Webp")]
 public class Vp8ResidualTests
 {
-    [Fact]
-    public void Vp8CostArray_Serialization_Works()
-    {
-        // arrange
-        Vp8CostArray expected = new();
-        for (ushort i = 0; i < expected.Costs.Length; i++)
-        {
-            expected.Costs[i] = i;
-        }
-
-        JsonSerializerOptions options = new()
-        {
-            Converters = { new Vp8CostArrayJsonConverter() }
-        };
-
-        // act
-        string jsonString = JsonSerializer.Serialize(expected);
-        Vp8CostArray actual = JsonSerializer.Deserialize<Vp8CostArray>(jsonString, options);
-
-        // assert
-        Assert.Equal(expected.Costs, actual.Costs);
-    }
-
     [Fact]
     public void Vp8Residual_Serialization_Works()
     {