chore: initial project import

backend/probe/tests/Monitor.Probe.Tests/ProbeTests.cs

@@ -0,0 +1,87 @@
+using Fleet.Core;
+using Fleet.Hosting;
+using Monitor.Protocol;
+
+namespace Monitor.Probe.Tests;
+
+public sealed class ProbeTests
+{
+    [Fact]
+    public void ClockEstimator_UsesTheSampleWithTheShortestRoundTrip()
+    {
+        var clock = new ClockEstimator();
+        Assert.False(clock.HasEstimate);
+
+        // Offset 1000 with a 50 ms round trip, offset 5000 with a 2 ms round trip (symmetry assumption is far better here)
+        clock.Add(sendUs: 0, agentUs: 25_000 + 1000, receiveUs: 50_000);
+        clock.Add(sendUs: 100_000, agentUs: 101_000 + 5000, receiveUs: 102_000);
+        Assert.True(clock.HasEstimate);
+        Assert.Equal(5000, clock.OffsetUs);
+
+        // Slow samples do not displace the good one
+        clock.Add(sendUs: 200_000, agentUs: 300_000, receiveUs: 400_000);
+        Assert.Equal(5000, clock.OffsetUs);
+    }
+
+    private static string NewDirectory()
+    {
+        string path = Path.Combine(Path.GetTempPath(), "probe-tests-" + Guid.NewGuid().ToString("N"));
+        Directory.CreateDirectory(path);
+        return path;
+    }
+
+    private static ProbeAgentsResult List(long version, params string[] ids) => new()
+    {
+        Version = version,
+        Agents = [.. ids.Select(id => new AgentEndpoint { AgentId = new NodeId(id), Host = id + ".example", TcpPort = 7443, Spki = "c3BraQ==" })],
+    };
+
+    [Fact]
+    public void AgentDirectory_StartsFromBootstrap_IgnoresStaleLists_PersistsChanges_AndReloadsThem()
+    {
+        string directory = NewDirectory();
+        try
+        {
+            var file = new ProbeFile { ProbeId = "prb_x", Bootstrap = [new BootstrapAgent { AgentId = "agt_boot", Host = "boot.example", TcpPort = 7443, Spki = "c3BraQ==" }] };
+            var directoryA = new AgentDirectory(new ConfigStore(directory), directory, file, NullNodeLog.Instance);
+            int changes = 0;
+            directoryA.Changed += () => changes++;
+            Assert.Equal(["agt_boot"], directoryA.Agents.Select(a => a.AgentId));
+
+            directoryA.Apply(List(5, "agt_1", "agt_2"));
+            Assert.Equal(1, changes);
+            Assert.Equal(["agt_1", "agt_2"], directoryA.Agents.Select(a => a.AgentId));
+
+            directoryA.Apply(List(4, "agt_old")); // out-of-order older push
+            directoryA.Apply(List(5, "agt_1", "agt_2")); // same version and content
+            Assert.Equal(1, changes);
+            Assert.Equal(5, directoryA.Version);
+
+            // The next start uses the saved list, not the bootstrap one
+            var directoryB = new AgentDirectory(new ConfigStore(directory), directory, file, NullNodeLog.Instance);
+            Assert.Equal(["agt_1", "agt_2"], directoryB.Agents.Select(a => a.AgentId));
+            Assert.Equal(5, directoryB.Version);
+        }
+        finally
+        {
+            Directory.Delete(directory, recursive: true);
+        }
+    }
+
+    [Fact]
+    public void AgentDirectory_FallsBackToBootstrap_WhenTheSavedFileIsCorrupt()
+    {
+        string directory = NewDirectory();
+        try
+        {
+            new ConfigStore(directory).Write(AgentDirectory.FileName, "{ not json"u8.ToArray());
+            var file = new ProbeFile { Bootstrap = [new BootstrapAgent { AgentId = "agt_boot", Host = "h", TcpPort = 1, Spki = "AA==" }] };
+            var loaded = new AgentDirectory(new ConfigStore(directory), directory, file, NullNodeLog.Instance);
+            Assert.Equal(["agt_boot"], loaded.Agents.Select(a => a.AgentId));
+        }
+        finally
+        {
+            Directory.Delete(directory, recursive: true);
+        }
+    }
+}