Add Galaxy repository API and clients

src/MxGateway.Tests/Galaxy/GalaxyHierarchyCacheTests.cs

@@ -0,0 +1,74 @@
+using MxGateway.Server.Galaxy;
+
+namespace MxGateway.Tests.Galaxy;
+
+public sealed class GalaxyHierarchyCacheTests
+{
+    [Fact]
+    public void Current_BeforeAnyRefresh_ReturnsEmpty()
+    {
+        GalaxyDeployNotifier notifier = new();
+        GalaxyHierarchyCache cache = CreateCache(notifier, new ManualTimeProvider());
+
+        GalaxyHierarchyCacheEntry entry = cache.Current;
+
+        Assert.Equal(GalaxyCacheStatus.Unknown, entry.Status);
+        Assert.False(entry.HasData);
+        Assert.Equal(0, entry.ObjectCount);
+        Assert.Null(entry.Reply);
+    }
+
+    [Fact]
+    public async Task RefreshAsync_WhenSqlIsUnreachable_MarksUnavailableAndDoesNotPublish()
+    {
+        GalaxyDeployNotifier notifier = new();
+        ManualTimeProvider clock = new(DateTimeOffset.Parse("2026-04-28T12:00:00Z"));
+        GalaxyHierarchyCache cache = CreateCache(notifier, clock);
+
+        await cache.RefreshAsync(CancellationToken.None);
+
+        Assert.Equal(GalaxyCacheStatus.Unavailable, cache.Current.Status);
+        Assert.False(string.IsNullOrWhiteSpace(cache.Current.LastError));
+        Assert.Null(notifier.Latest);
+        Assert.True(cache.WaitForFirstLoadAsync(CancellationToken.None).IsCompletedSuccessfully);
+    }
+
+    [Fact]
+    public void HasData_OnHealthyEntry_IsTrue()
+    {
+        GalaxyHierarchyCacheEntry entry = GalaxyHierarchyCacheEntry.Empty with
+        {
+            Status = GalaxyCacheStatus.Healthy,
+            LastSuccessAt = DateTimeOffset.UtcNow,
+            ObjectCount = 1,
+        };
+
+        Assert.True(entry.HasData);
+    }
+
+    [Fact]
+    public void HasData_OnUnknownEntry_IsFalse()
+    {
+        Assert.False(GalaxyHierarchyCacheEntry.Empty.HasData);
+    }
+
+    private static GalaxyHierarchyCache CreateCache(GalaxyDeployNotifier notifier, TimeProvider clock)
+    {
+        GalaxyRepositoryOptions options = new()
+        {
+            ConnectionString = "Server=127.0.0.1,65500;Database=ZB;Connection Timeout=1;Encrypt=False;",
+            CommandTimeoutSeconds = 1,
+        };
+        GalaxyRepository repository = new(options);
+        return new GalaxyHierarchyCache(repository, notifier, clock);
+    }
+
+    private sealed class ManualTimeProvider(DateTimeOffset start = default) : TimeProvider
+    {
+        private DateTimeOffset _now = start == default ? DateTimeOffset.UtcNow : start;
+
+        public override DateTimeOffset GetUtcNow() => _now;
+
+        public void Advance(TimeSpan duration) => _now += duration;
+    }
+}