Merge branch 'fix/archreview-crit1-split-brain-resolver'

2026-07-09 06:07:33 -04:00
parent 025aac4d58 eaf78aad90
commit 0ed30483b4
6 changed files with 257 additions and 6 deletions
@@ -0,0 +1,58 @@
+using Akka.Cluster.Hosting;
+using Akka.Cluster.Hosting.SBR;
+using Shouldly;
+using Xunit;
+
+namespace ZB.MOM.WW.OtOpcUa.Cluster.Tests;
+
+/// <summary>
+/// Guards that the split-brain-resolver strategy stays set <b>explicitly in code</b> (arch-review 03/S1,
+/// premise corrected — see #11). Akka.Cluster.Hosting already enables an SBR downing provider by default
+/// (it applies <c>SplitBrainResolverOption.Default</c> when <see cref="ClusterOptions.SplitBrainResolver"/>
+/// is null, which reads the akka.conf <c>keep-oldest</c> block), so the cluster is not NoDowning even
+/// without the typed option. These tests assert
+/// <see cref="ServiceCollectionExtensions.BuildClusterOptions"/> sets the typed
+/// <c>KeepOldestOption { DownIfAlone = true }</c> so the strategy is explicit in code rather than relying on
+/// the framework default — a future refactor cannot silently drop that explicitness. (Failover behaviour is
+/// separately verified by <c>HardKillFailoverTests</c>, which passes regardless of activation path.)
+/// </summary>
+public sealed class SplitBrainResolverActivationTests
+{
+    private static AkkaClusterOptions SampleOptions() => new()
+    {
+        SeedNodes = new[] { "akka.tcp://otopcua@127.0.0.1:4053" },
+        Roles = new[] { "admin", "driver" },
+    };
+
+    /// <summary>Verifies the cluster options carry an explicit split-brain resolver strategy.</summary>
+    [Fact]
+    public void BuildClusterOptions_sets_an_explicit_split_brain_resolver()
+    {
+        var options = ServiceCollectionExtensions.BuildClusterOptions(SampleOptions());
+
+        options.SplitBrainResolver.ShouldNotBeNull(
+            "SplitBrainResolver must be set explicitly in code — keeps the strategy independent of Akka.Cluster.Hosting's default provider rather than relying on it.");
+    }
+
+    /// <summary>Verifies the resolver is keep-oldest with down-if-alone (correct for a 2-node pair).</summary>
+    [Fact]
+    public void BuildClusterOptions_uses_keep_oldest_with_down_if_alone()
+    {
+        var options = ServiceCollectionExtensions.BuildClusterOptions(SampleOptions());
+
+        var keepOldest = options.SplitBrainResolver.ShouldBeOfType<KeepOldestOption>();
+        keepOldest.DownIfAlone.ShouldBe(true);
+    }
+
+    /// <summary>Verifies seed nodes and roles are still threaded through unchanged.</summary>
+    [Fact]
+    public void BuildClusterOptions_preserves_seed_nodes_and_roles()
+    {
+        var input = SampleOptions();
+
+        var options = ServiceCollectionExtensions.BuildClusterOptions(input);
+
+        options.SeedNodes.ShouldBe(input.SeedNodes);
+        options.Roles.ShouldBe(input.Roles);
+    }
+}