spectre.console/test/Spectre.Console.Tests/Unit/Widgets/CanvasTests.cs

namespace Spectre.Console.Tests.Unit;

[UsesVerify]
[ExpectationPath("Widgets/Canvas")]
public class CanvasTests
{
    public sealed class TheConstructor
    {
        [Fact]
        public void Should_Throw_If_Width_Is_Less_Than_Zero()
        {
            // Given, When
            var result = Record.Exception(() => new Canvas(0, 1));

            // Then
            result.ShouldBeOfType<ArgumentException>()
                .And(ex => ex.ParamName.ShouldBe("width"));
        }

        [Fact]
        public void Should_Throw_If_Height_Is_Less_Than_Zero()
        {
            // Given, When
            var result = Record.Exception(() => new Canvas(1, 0));

            // Then
            result.ShouldBeOfType<ArgumentException>()
                .And(ex => ex.ParamName.ShouldBe("height"));
        }
    }

    [Fact]
    [Expectation("Render")]
    public async Task Should_Render_Canvas_Correctly()
    {
        // Given
        var console = new TestConsole()
            .Colors(ColorSystem.Standard)
            .EmitAnsiSequences();

        var canvas = new Canvas(width: 5, height: 5);
        canvas.SetPixel(0, 0, Color.Red);
        canvas.SetPixel(4, 0, Color.Green);
        canvas.SetPixel(0, 4, Color.Blue);
        canvas.SetPixel(4, 4, Color.Yellow);

        // When
        console.Write(canvas);

        // Then
        await Verifier.Verify(console.Output);
    }

    [Fact]
    [Expectation("Render_Nested")]
    public async Task Simple_Measure()
    {
        // Given
        var console = new TestConsole()
            .Colors(ColorSystem.Standard)
            .EmitAnsiSequences();

        var panel = new Panel(new Canvas(width: 2, height: 2)
            .SetPixel(0, 0, Color.Aqua)
            .SetPixel(1, 1, Color.Grey));

        // When
        console.Write(panel);

        // Then
        await Verifier.Verify(console.Output);
    }

    [Fact]
    [Expectation("Render_NarrowTerminal")]
    public async Task Should_Scale_Down_Canvas_Is_Bigger_Than_Terminal()
    {
        // Given
        var console = new TestConsole()
            .Width(10)
            .Colors(ColorSystem.Standard)
            .EmitAnsiSequences();

        var canvas = new Canvas(width: 20, height: 10);
        canvas.SetPixel(0, 0, Color.Aqua);
        canvas.SetPixel(19, 9, Color.Grey);

        // When
        console.Write(canvas);

        // Then
        await Verifier.Verify(console.Output);
    }

    [Fact]
    [Expectation("Render_MaxWidth")]
    public async Task Should_Scale_Down_Canvas_If_MaxWidth_Is_Set()
    {
        // Given
        var console = new TestConsole()
            .Colors(ColorSystem.Standard)
            .EmitAnsiSequences();

        var canvas = new Canvas(width: 20, height: 10) { MaxWidth = 10 };
        canvas.SetPixel(0, 0, Color.Aqua);
        canvas.SetPixel(19, 9, Color.Aqua);

        // When
        console.Write(canvas);

        // Then
        await Verifier.Verify(console.Output);
    }

    [Fact]
    public void Should_Not_Render_Canvas_If_Canvas_Cannot_Be_Scaled_Down()
    {
        // Given
        var console = new TestConsole()
            .Width(10)
            .Colors(ColorSystem.Standard)
            .EmitAnsiSequences();

        var canvas = new Canvas(width: 20, height: 2);
        canvas.SetPixel(0, 0, Color.Aqua);
        canvas.SetPixel(19, 1, Color.Grey);

        // When
        console.Write(canvas);

        // Then
        console.Output.ShouldBeEmpty();
    }
}