Add unit tests for various services and functionalities

- Implement tests for ChatLine utility methods including color tag detection and stripping.
- Create comprehensive tests for CommandHandler to validate command handling and status updates.
- Add tests for DataMigrationService to ensure correct ANSI to color tag conversion.
- Enhance FileValidationHelperTests with audio file validation tests.
- Introduce ImageToAsciiServiceTests to verify image dimension retrieval.
- Develop IrcMessageFormatterTests for message formatting and color tag conversion.
- Add JwtTokenServiceTests to validate JWT token generation and hashing.
- Implement LinkEmbedServiceTests for URL extraction and Open Graph tag parsing.
- Update EchoHub.Tests.csproj to include necessary project references.

src/EchoHub.Tests/IrcMessageFormatterTests.cs

@@ -0,0 +1,186 @@
+using EchoHub.Core.DTOs;
+using EchoHub.Core.Models;
+using EchoHub.Server.Irc;
+using Xunit;
+
+namespace EchoHub.Tests;
+
+public class IrcMessageFormatterTests
+{
+    private static MessageDto CreateMessage(
+        MessageType type = MessageType.Text,
+        string content = "hello",
+        string sender = "alice",
+        string channel = "general",
+        string? attachmentUrl = null,
+        string? attachmentFileName = null,
+        List<EmbedDto>? embeds = null) => new(
+        Id: Guid.NewGuid(),
+        Content: content,
+        SenderUsername: sender,
+        SenderNicknameColor: null,
+        ChannelName: channel,
+        Type: type,
+        AttachmentUrl: attachmentUrl,
+        AttachmentFileName: attachmentFileName,
+        SentAt: DateTimeOffset.UtcNow,
+        Embeds: embeds);
+
+    // ── FormatMessage ─────────────────────────────────────────────────
+
+    [Fact]
+    public void FormatMessage_TextMessage_FormatsAsPRIVMSG()
+    {
+        var msg = CreateMessage(content: "Hello world");
+        var lines = IrcMessageFormatter.FormatMessage(msg);
+
+        Assert.Single(lines);
+        Assert.Contains("PRIVMSG #general :Hello world", lines[0]);
+        Assert.StartsWith(":alice!alice@echohub", lines[0]);
+    }
+
+    [Fact]
+    public void FormatMessage_TextMessage_WithEmbeds_AppendsEmbedLines()
+    {
+        var embeds = new List<EmbedDto>
+        {
+            new("GitHub", "Repo Title", "A description", null, "https://github.com/test")
+        };
+        var msg = CreateMessage(content: "check this out https://github.com/test", embeds: embeds);
+        var lines = IrcMessageFormatter.FormatMessage(msg);
+
+        Assert.True(lines.Count >= 2);
+        Assert.Contains("PRIVMSG #general :check this out", lines[0]);
+        // Embed lines contain the Unicode pipe char and site/title
+        Assert.Contains("GitHub", lines[1]);
+        Assert.Contains("Repo Title", lines[1]);
+    }
+
+    [Fact]
+    public void FormatMessage_ImageMessage_IncludesImageTagAndDownloadUrl()
+    {
+        var msg = CreateMessage(
+            type: MessageType.Image,
+            content: "{F:FF0000}\u2588{X}",
+            attachmentUrl: "/api/files/abc",
+            attachmentFileName: "photo.png");
+        var lines = IrcMessageFormatter.FormatMessage(msg);
+
+        Assert.True(lines.Count >= 2);
+        Assert.Contains("[Image: photo.png]", lines[0]);
+        Assert.Contains("Download: /api/files/abc", lines[1]);
+    }
+
+    [Fact]
+    public void FormatMessage_FileMessage_IncludesFileTag()
+    {
+        var msg = CreateMessage(
+            type: MessageType.File,
+            content: "report.pdf",
+            attachmentUrl: "/api/files/xyz",
+            attachmentFileName: "report.pdf");
+        var lines = IrcMessageFormatter.FormatMessage(msg);
+
+        Assert.Single(lines);
+        Assert.Contains("[File: report.pdf]", lines[0]);
+        Assert.Contains("/api/files/xyz", lines[0]);
+    }
+
+    [Fact]
+    public void FormatMessage_AudioMessage_IncludesMusicNoteAndAudioTag()
+    {
+        var msg = CreateMessage(
+            type: MessageType.Audio,
+            content: "song.mp3",
+            attachmentUrl: "/api/files/def",
+            attachmentFileName: "song.mp3");
+        var lines = IrcMessageFormatter.FormatMessage(msg);
+
+        Assert.Single(lines);
+        Assert.Contains("\u266a", lines[0]); // ♪
+        Assert.Contains("[Audio: song.mp3]", lines[0]);
+        Assert.Contains("/api/files/def", lines[0]);
+    }
+
+    // ── ColorTagsToAnsi ───────────────────────────────────────────────
+
+    [Fact]
+    public void ColorTagsToAnsi_ForegroundTag_ConvertsToAnsiEscape()
+    {
+        var result = IrcMessageFormatter.ColorTagsToAnsi("{F:FF0000}text");
+        Assert.Contains("\x1b[38;2;255;0;0m", result);
+        Assert.Contains("text", result);
+    }
+
+    [Fact]
+    public void ColorTagsToAnsi_BackgroundTag_ConvertsToAnsiEscape()
+    {
+        var result = IrcMessageFormatter.ColorTagsToAnsi("{B:00FF00}text");
+        Assert.Contains("\x1b[48;2;0;255;0m", result);
+    }
+
+    [Fact]
+    public void ColorTagsToAnsi_ResetTag_ConvertsToAnsiReset()
+    {
+        var result = IrcMessageFormatter.ColorTagsToAnsi("{X}");
+        Assert.Equal("\x1b[0m", result);
+    }
+
+    [Fact]
+    public void ColorTagsToAnsi_NoTags_ReturnsUnchanged()
+    {
+        var result = IrcMessageFormatter.ColorTagsToAnsi("plain text");
+        Assert.Equal("plain text", result);
+    }
+
+    [Fact]
+    public void ColorTagsToAnsi_MultipleTags_ConvertsAll()
+    {
+        var result = IrcMessageFormatter.ColorTagsToAnsi("{F:FF0000}red{F:0000FF}blue{X}");
+        Assert.Contains("\x1b[38;2;255;0;0m", result);
+        Assert.Contains("\x1b[38;2;0;0;255m", result);
+        Assert.Contains("\x1b[0m", result);
+        Assert.Contains("red", result);
+        Assert.Contains("blue", result);
+    }
+
+    // ── SplitMessage ──────────────────────────────────────────────────
+
+    [Fact]
+    public void SplitMessage_ShortMessage_ReturnsSingleChunk()
+    {
+        var result = IrcMessageFormatter.SplitMessage("Hello", 400);
+        Assert.Single(result);
+        Assert.Equal("Hello", result[0]);
+    }
+
+    [Fact]
+    public void SplitMessage_LongMessage_SplitsAtWordBoundary()
+    {
+        var words = string.Join(" ", Enumerable.Repeat("word", 200));
+        var result = IrcMessageFormatter.SplitMessage(words, 50);
+
+        Assert.True(result.Count > 1);
+        foreach (var chunk in result)
+            Assert.True(System.Text.Encoding.UTF8.GetByteCount(chunk) <= 50);
+    }
+
+    [Fact]
+    public void SplitMessage_EmptyMessage_ReturnsSingleEmptyChunk()
+    {
+        var result = IrcMessageFormatter.SplitMessage("", 400);
+        Assert.Single(result);
+        Assert.Equal("", result[0]);
+    }
+
+    [Fact]
+    public void SplitMessage_SingleLongWord_KeptAsOneChunk()
+    {
+        var longWord = new string('a', 500);
+        var result = IrcMessageFormatter.SplitMessage(longWord, 400);
+
+        // Single word can't be split at word boundary, so it stays as one chunk
+        Assert.Single(result);
+        Assert.Equal(longWord, result[0]);
+    }
+}