A:添加测试项目

src/Sharp/Config/ConfigSource.cs

@@ -0,0 +1,31 @@
+using System.Diagnostics.CodeAnalysis;
+
+namespace Sharp.Config;
+
+public sealed class ConfigSource
+{
+    public required string Path { get; init; }
+    public required ConfigFormat Format { get; init; }
+    public bool Optional { get; init; } = true;
+
+    public override string ToString() => $"{Format}:{Path} (Optional={Optional})";
+
+    public static bool TryGuess(string path, [NotNullWhen(true)] out ConfigSource? source)
+    {
+        source = null;
+        var ext = System.IO.Path.GetExtension(path).ToLowerInvariant();
+        var fmt = ext switch
+        {
+            ".json" => ConfigFormat.Json,
+            ".ini" => ConfigFormat.Ini,
+            ".xml" => ConfigFormat.Xml,
+            ".toml" => ConfigFormat.Toml,
+            _ => (ConfigFormat?)null
+        };
+
+        if (fmt is null) return false;
+        source = new ConfigSource { Path = path, Format = fmt.Value };
+        return true;
+    }
+}
+