ttui/test/TinyTUI.Tests/Text/TerminalTextMeasurerTests.cs

using TinyTUI.Text;

namespace TinyTUI.Tests.Text;

public sealed class TerminalTextMeasurerTests
{
    private readonly TerminalTextMeasurer _measurer = new();

    [Fact]
    public void GetWidthHandlesAnsiTabsAndEmojiGraphemes()
    {
        Assert.Equal(5, _measurer.GetWidth("\t\e[31m界\e[0m"));
        Assert.Equal(2, _measurer.GetWidth("🇨"));
        Assert.Equal(2, _measurer.GetWidth("🇨🇳"));
        Assert.Equal(2, _measurer.GetWidth("👨‍💻"));
        Assert.Equal(2, _measurer.GetWidth("⚡️"));
    }

    [Fact]
    public void SliceTracksTabColumnsAndMeasuredWidth()
    {
        var strictTabSlice = _measurer.Slice("out 192M\t.pi/skill-tests/results-ha", 0, 10, strict: true);
        Assert.Equal("out 192M", strictTabSlice.Text);
        Assert.Equal(8, strictTabSlice.Width);
        Assert.Equal(_measurer.GetWidth(strictTabSlice.Text), strictTabSlice.Width);

        var afterTabSlice = _measurer.Slice("out 192M\t.pi/skill-tests/results-ha", 13, 10, strict: true);
        Assert.Equal("i/skill-te", afterTabSlice.Text);
        Assert.Equal(_measurer.GetWidth(afterTabSlice.Text), afterTabSlice.Width);
    }

    [Fact]
    public void TruncateKeepsAnsiPrefixAndBracketsEllipsis()
    {
        var ansiText = $"\e[31m{string.Concat(Enumerable.Repeat("hello ", 100))}\e[0m";
        var truncated = _measurer.Truncate(ansiText, 20, "…");

        Assert.True(_measurer.GetWidth(truncated) <= 20);
        Assert.Contains("\e[31m", truncated, StringComparison.Ordinal);
        Assert.EndsWith("\e[0m…\e[0m", truncated, StringComparison.Ordinal);
        Assert.Equal("\e[0m🙂\e[0m", _measurer.Truncate("abcdef", 2, "🙂"));
        Assert.Equal(string.Empty, _measurer.Truncate("abcdef", 1, "🙂"));
    }

    [Fact]
    public void WrapRestoresAnsiAndOsc8AcrossLines()
    {
        var redWrapped = _measurer.Wrap($"\e[31mhello world this is red\e[0m", 10);
        Assert.All(redWrapped.Skip(1), line => Assert.StartsWith("\e[31m", line, StringComparison.Ordinal));
        Assert.All(redWrapped.Take(redWrapped.Count - 1), line => Assert.False(line.EndsWith("\e[0m", StringComparison.Ordinal)));

        var hyperlink = "\e]8;;https://example.com\a0123456789\e]8;;\a";
        var hyperlinkWrapped = _measurer.Wrap(hyperlink, 6);
        Assert.True(hyperlinkWrapped.Count > 1);
        Assert.All(hyperlinkWrapped, line => Assert.Contains("\e]8;;https://example.com\a", line, StringComparison.Ordinal));
        Assert.All(hyperlinkWrapped.Take(hyperlinkWrapped.Count - 1), line => Assert.EndsWith("\e]8;;\a", line, StringComparison.Ordinal));
    }
}