Add repo-guard meta tests

Trax.Dashboard.slnx

@@ -4,5 +4,6 @@
   </Folder>
   <Folder Name="/tests/">
     <Project Path="tests/Trax.Dashboard.Tests.Integration/Trax.Dashboard.Tests.Integration.csproj" />
+    <Project Path="tests/Trax.Dashboard.Tests.Meta/Trax.Dashboard.Tests.Meta.csproj" />
   </Folder>
 </Solution>

tests/Trax.Dashboard.Tests.Meta/GlobalUsings.cs

@@ -0,0 +1,9 @@
+global using System;
+global using System.Collections.Generic;
+global using System.IO;
+global using System.Linq;
+global using System.Text.RegularExpressions;
+global using System.Xml.Linq;
+global using FluentAssertions;
+global using NUnit.Framework;
+global using Trax.Dashboard.Tests.Meta.Infrastructure;

tests/Trax.Dashboard.Tests.Meta/Infrastructure/RepoRoot.cs

@@ -0,0 +1,28 @@
+namespace Trax.Dashboard.Tests.Meta.Infrastructure;
+
+internal static class RepoRoot
+{
+    private static readonly Lazy<string> Cached = new(Resolve);
+
+    public static string Path => Cached.Value;
+
+    public static string Combine(params string[] segments) =>
+        System.IO.Path.Combine(new[] { Path }.Concat(segments).ToArray());
+
+    public static string Relative(string absolute) =>
+        System.IO.Path.GetRelativePath(Path, absolute);
+
+    private static string Resolve()
+    {
+        var dir = new DirectoryInfo(AppContext.BaseDirectory);
+        while (dir is not null)
+        {
+            if (dir.EnumerateFiles("*.slnx").Any())
+                return dir.FullName;
+            dir = dir.Parent;
+        }
+        throw new InvalidOperationException(
+            $"Could not locate repository root: no .slnx found walking up from '{AppContext.BaseDirectory}'."
+        );
+    }
+}

tests/Trax.Dashboard.Tests.Meta/Infrastructure/SourceFiles.cs

@@ -0,0 +1,43 @@
+namespace Trax.Dashboard.Tests.Meta.Infrastructure;
+
+internal static class SourceFiles
+{
+    public static IEnumerable<string> CSharp(params string[] subdirs) => Enumerate("*.cs", subdirs);
+
+    public static IEnumerable<string> Projects(params string[] subdirs) =>
+        Enumerate("*.csproj", subdirs);
+
+    public static IEnumerable<string> Markdown(params string[] subdirs) =>
+        Enumerate("*.md", subdirs);
+
+    private static IEnumerable<string> Enumerate(string pattern, string[] subdirs)
+    {
+        var roots =
+            subdirs.Length == 0
+                ? new[] { RepoRoot.Path }
+                : subdirs.Select(s => Path.Combine(RepoRoot.Path, s)).ToArray();
+
+        foreach (var root in roots)
+        {
+            if (!Directory.Exists(root))
+                continue;
+            foreach (
+                var file in Directory.EnumerateFiles(root, pattern, SearchOption.AllDirectories)
+            )
+            {
+                if (IsExcluded(file))
+                    continue;
+                yield return file;
+            }
+        }
+    }
+
+    private static bool IsExcluded(string path)
+    {
+        var s = Path.DirectorySeparatorChar;
+        return path.Contains($"{s}bin{s}", StringComparison.Ordinal)
+            || path.Contains($"{s}obj{s}", StringComparison.Ordinal)
+            || path.Contains($"{s}node_modules{s}", StringComparison.Ordinal)
+            || path.Contains($"{s}.git{s}", StringComparison.Ordinal);
+    }
+}

tests/Trax.Dashboard.Tests.Meta/Infrastructure/SourceText.cs

@@ -0,0 +1,47 @@
+namespace Trax.Dashboard.Tests.Meta.Infrastructure;
+
+internal static class SourceText
+{
+    private static readonly Regex BlockComment = new(
+        "/\\*.*?\\*/",
+        RegexOptions.Singleline | RegexOptions.Compiled
+    );
+    private static readonly Regex LineComment = new("//[^\\r\\n]*", RegexOptions.Compiled);
+    private static readonly Regex VerbatimString = new(
+        "@\"(?:[^\"]|\"\")*\"",
+        RegexOptions.Compiled
+    );
+    private static readonly Regex InterpolatedVerbatim = new(
+        "\\$@\"(?:[^\"]|\"\")*\"",
+        RegexOptions.Compiled
+    );
+    private static readonly Regex RegularString = new(
+        "\"(?:\\\\.|[^\"\\\\])*\"",
+        RegexOptions.Compiled
+    );
+
+    public static string StripCommentsAndStrings(string source)
+    {
+        var s = BlockComment.Replace(source, " ");
+        s = LineComment.Replace(s, " ");
+        s = InterpolatedVerbatim.Replace(s, "\"\"");
+        s = VerbatimString.Replace(s, "\"\"");
+        s = RegularString.Replace(s, "\"\"");
+        return s;
+    }
+
+    public static IReadOnlyList<(int LineNumber, string Line)> MatchingLines(
+        string source,
+        Regex pattern
+    )
+    {
+        var hits = new List<(int, string)>();
+        var lines = source.Replace("\r\n", "\n").Split('\n');
+        for (var i = 0; i < lines.Length; i++)
+        {
+            if (pattern.IsMatch(lines[i]))
+                hits.Add((i + 1, lines[i]));
+        }
+        return hits;
+    }
+}