DiagramTests.cs

using Blazor.Diagrams.Core.Geometry;
using Blazor.Diagrams.Core.Models;
using FluentAssertions;
using Xunit;

namespace Blazor.Diagrams.Core.Tests
{
    public class DiagramTests
    {
        [Fact]
        public void GetScreenPoint_ShouldReturnCorrectPoint()
        {
            // Arrange
            var diagram = new Diagram();

            // Act
            diagram.SetZoom(1.234);
            diagram.UpdatePan(50, 50);
            diagram.SetContainer(new Rectangle(30, 65, 1000, 793));
            var pt = diagram.GetScreenPoint(100, 200);

            // Assert
            pt.X.Should().Be(203.4); // 2*X + panX + left
            pt.Y.Should().Be(361.8); // 2*Y + panY + top
        }

        [Fact]
        public void ZoomToFit_ShouldUseSelectedNodesIfAny()
        {
            // Arrange
            var diagram = new Diagram();
            diagram.SetContainer(new Rectangle(new Point(0, 0), new Size(1080, 768)));
            diagram.Nodes.Add(new NodeModel(new Point(50, 50))
            {
                Size = new Size(100, 80)
            });
            diagram.SelectModel(diagram.Nodes[0], true);

            // Act
            diagram.ZoomToFit(10);

            // Assert
            diagram.Zoom.Should().BeApproximately(7.68, 0.001);
            diagram.Pan.X.Should().Be(-307.2);
            diagram.Pan.Y.Should().Be(-307.2);
        }

        [Fact]
        public void ZoomToFit_ShouldUseNodesWhenNoneSelected()
        {
            // Arrange
            var diagram = new Diagram();
            diagram.SetContainer(new Rectangle(new Point(0, 0), new Size(1080, 768)));
            diagram.Nodes.Add(new NodeModel(new Point(50, 50))
            {
                Size = new Size(100, 80)
            });

            // Act
            diagram.ZoomToFit(10);

            // Assert
            diagram.Zoom.Should().BeApproximately(7.68, 0.001);
            diagram.Pan.X.Should().Be(-307.2);
            diagram.Pan.Y.Should().Be(-307.2);
        }

        [Fact]
        public void ZoomToFit_ShouldTriggerAppropriateEvents()
        {
            // Arrange
            var diagram = new Diagram();
            diagram.SetContainer(new Rectangle(new Point(0, 0), new Size(1080, 768)));
            diagram.Nodes.Add(new NodeModel(new Point(50, 50))
            {
                Size = new Size(100, 80)
            });

            var refreshes = 0;
            var zoomChanges = 0;
            var panChanges = 0;

            // Act
            diagram.Changed += () => refreshes++;
            diagram.ZoomChanged += () => zoomChanges++;
            diagram.PanChanged += () => panChanges++;
            diagram.ZoomToFit(10);

            // Assert
            refreshes.Should().Be(1);
            zoomChanges.Should().Be(1);
            panChanges.Should().Be(1);
        }
    }
}