ImageSharp/tests/ImageSharp.Tests/Formats/Jpg/JFifMarkerTests.cs

// Copyright (c) Six Labors.
// Licensed under the Six Labors Split License.

using SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder;
using SixLabors.ImageSharp.Metadata;

namespace SixLabors.ImageSharp.Tests.Formats.Jpg;

[Trait("Format", "Jpg")]
public class JFifMarkerTests
{
    // Taken from actual test image
    private readonly byte[] bytes = [0x4A, 0x46, 0x49, 0x46, 0x0, 0x1, 0x1, 0x1, 0x0, 0x60, 0x0, 0x60, 0x0];

    // Altered components
    private readonly byte[] bytes2 = [0x4A, 0x46, 0x49, 0x46, 0x0, 0x1, 0x1, 0x1, 0x0, 0x48, 0x0, 0x48, 0x0];

    // Incorrect density values. Zero is invalid.
    private readonly byte[] bytes3 = [0x4A, 0x46, 0x49, 0x46, 0x0, 0x1, 0x1, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0];

    [Fact]
    public void MarkerLengthIsCorrect()
    {
        Assert.Equal(13, JFifMarker.Length);
    }

    [Fact]
    public void MarkerReturnsCorrectParsedValue()
    {
        bool isJFif = JFifMarker.TryParse(this.bytes, out JFifMarker marker);

        Assert.True(isJFif);
        Assert.Equal(1, marker.MajorVersion);
        Assert.Equal(1, marker.MinorVersion);
        Assert.Equal(PixelResolutionUnit.PixelsPerInch, marker.DensityUnits);
        Assert.Equal(96, marker.XDensity);
        Assert.Equal(96, marker.YDensity);
    }

    [Fact]
    public void MarkerIgnoresIncorrectValue()
    {
        bool isJFif = JFifMarker.TryParse([0, 0, 0, 0], out JFifMarker marker);

        Assert.False(isJFif);
        Assert.Equal(default, marker);
    }

    [Fact]
    public void MarkerEqualityIsCorrect()
    {
        JFifMarker.TryParse(this.bytes, out JFifMarker marker);
        JFifMarker.TryParse(this.bytes, out JFifMarker marker2);

        Assert.True(marker.Equals(marker2));
    }

    [Fact]
    public void MarkerInEqualityIsCorrect()
    {
        JFifMarker.TryParse(this.bytes, out JFifMarker marker);
        JFifMarker.TryParse(this.bytes2, out JFifMarker marker2);

        Assert.False(marker.Equals(marker2));
    }

    [Fact]
    public void MarkerHashCodeIsReplicable()
    {
        JFifMarker.TryParse(this.bytes, out JFifMarker marker);
        JFifMarker.TryParse(this.bytes, out JFifMarker marker2);

        Assert.True(marker.GetHashCode().Equals(marker2.GetHashCode()));
    }

    [Fact]
    public void MarkerHashCodeIsUnique()
    {
        JFifMarker.TryParse(this.bytes, out JFifMarker marker);
        JFifMarker.TryParse(this.bytes2, out JFifMarker marker2);

        Assert.False(marker.GetHashCode().Equals(marker2.GetHashCode()));
    }
}