feat(load-index): emit data.card_master_hash on mismatch (tier-1 freshness gate)

SVSim.UnitTests/Controllers/LoadControllerCardMasterHashTests.cs

@@ -0,0 +1,74 @@
+using System.Net;
+using System.Text;
+using System.Text.Json;
+using SVSim.UnitTests.Infrastructure;
+
+namespace SVSim.UnitTests.Controllers;
+
+/// <summary>
+/// Covers the response side of card-master freshness: server emits inner
+/// <c>data.card_master_hash</c> on <c>/load/index</c> only when the request's hash differs
+/// from <c>CardMasterConfig.CurrentHash</c>. Presence-only client check + emit-every-time
+/// would force a 1.27 MB redownload on every boot.
+/// </summary>
+public class LoadControllerCardMasterHashTests
+{
+    private const string PinnedHash = "94b5c44edc51ff76c0af8fcc894af12f979dd38c:1";
+
+    private static string IndexRequestJsonWithHash(string hash) =>
+        $$"""{"viewer_id":"0","steam_id":0,"steam_session_ticket":"","carrier":"steam","card_master_hash":"{{hash}}"}""";
+
+    [Test]
+    public async Task Index_omits_card_master_hash_when_request_matches_server_hash()
+    {
+        using var factory = new SVSimTestFactory();
+        long viewerId = await factory.SeedViewerAsync();
+        using var client = factory.CreateAuthenticatedClient(viewerId);
+
+        var response = await client.PostAsync("/load/index",
+            new StringContent(IndexRequestJsonWithHash(PinnedHash), Encoding.UTF8, "application/json"));
+
+        var body = await response.Content.ReadAsStringAsync();
+        Assert.That(response.StatusCode, Is.EqualTo(HttpStatusCode.OK), body);
+
+        using var doc = JsonDocument.Parse(body);
+        Assert.That(doc.RootElement.TryGetProperty("card_master_hash", out _), Is.False,
+            "Expected card_master_hash OMITTED when request matches server. Body: " + body);
+    }
+
+    [Test]
+    public async Task Index_emits_card_master_hash_when_request_differs()
+    {
+        using var factory = new SVSimTestFactory();
+        long viewerId = await factory.SeedViewerAsync();
+        using var client = factory.CreateAuthenticatedClient(viewerId);
+
+        var response = await client.PostAsync("/load/index",
+            new StringContent(IndexRequestJsonWithHash("oldhash:1"), Encoding.UTF8, "application/json"));
+
+        var body = await response.Content.ReadAsStringAsync();
+        using var doc = JsonDocument.Parse(body);
+        Assert.That(doc.RootElement.TryGetProperty("card_master_hash", out var hashEl), Is.True,
+            "Expected card_master_hash PRESENT when request differs. Body: " + body);
+        Assert.That(hashEl.GetString(), Is.EqualTo(PinnedHash));
+    }
+
+    [Test]
+    public async Task Index_emits_card_master_hash_when_request_hash_empty()
+    {
+        // Empty hash = fresh client with no cardmaster/card_master_1 on disk
+        // (CardMasterLocalFileUtility.GetCardMasterHash returns ""). Treat as mismatch.
+        using var factory = new SVSimTestFactory();
+        long viewerId = await factory.SeedViewerAsync();
+        using var client = factory.CreateAuthenticatedClient(viewerId);
+
+        var response = await client.PostAsync("/load/index",
+            new StringContent(IndexRequestJsonWithHash(""), Encoding.UTF8, "application/json"));
+
+        var body = await response.Content.ReadAsStringAsync();
+        using var doc = JsonDocument.Parse(body);
+        Assert.That(doc.RootElement.TryGetProperty("card_master_hash", out var hashEl), Is.True,
+            "Expected card_master_hash PRESENT for fresh client. Body: " + body);
+        Assert.That(hashEl.GetString(), Is.EqualTo(PinnedHash));
+    }
+}