Writing some tests, namely the fake game server

tests/FakeGameServer/Output.cs

@@ -0,0 +1,30 @@
+using System.Globalization;
+using System.Text.Json;
+
+namespace FakeGameServer;
+
+internal static class FakeOutput
+{
+    public static void Log(string category, string message) =>
+        Console.Out.WriteLine($"{Stamp()} [{category}] {message}");
+
+    // Mimics the real game's crash handling: print the error, write a crash log under
+    // <dataPath>/Logs, and exit with a code that is 0 unless a test asks otherwise.
+    public static int Crash(string dataPath, int exitCode, string message)
+    {
+        var text = $"{Stamp()}: Critical error occurred{Environment.NewLine}{message}";
+        Console.Out.WriteLine(text);
+        var logDir = Path.Combine(dataPath, "Logs");
+        Directory.CreateDirectory(logDir);
+        File.WriteAllText(Path.Combine(logDir, "server-crash.log"), text + Environment.NewLine);
+        return exitCode;
+    }
+
+    private static string Stamp() =>
+        DateTime.Now.ToString("dd.MM.yyyy HH:mm:ss", CultureInfo.InvariantCulture);
+}
+
+internal static class JsonOptions
+{
+    public static readonly JsonSerializerOptions Indented = new() { WriteIndented = true };
+}