Auto: opcuaclient-11 — reverse connect (server-initiated)

Closes #283

tests/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.IntegrationTests/OpcPlcReverseConnectFixture.cs

@@ -0,0 +1,56 @@
+namespace ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.IntegrationTests;
+
+/// <summary>
+///     Fixture for the reverse-connect variant of opc-plc (PR-11). Unlike the
+///     dial-mode <see cref="OpcPlcFixture"/>, the simulator here is the dialer:
+///     it reaches OUT to the test runner's listener URL on
+///     <c>opc.tcp://host.docker.internal:4844</c>. The fixture's job is to
+///     advertise the listener URL the test should bind and provide a clear
+///     skip reason when the docker-compose service isn't running.
+/// </summary>
+/// <remarks>
+///     <para>
+///         <b>Why no port-probe</b>: the conventional fixture probes the simulator's
+///         server port to detect docker-up. In reverse-connect the simulator opens
+///         no inbound port — it's a pure dialer — so a probe would always fail.
+///         Tests that want a hard skip should look at <see cref="SkipReason"/>
+///         which is set from the <c>OPCUA_RC_SIM</c> env var (any value =
+///         "simulator running"; absent = skip).
+///     </para>
+///     <para>
+///         The "shared listener URL" model is enforced by the driver's
+///         <c>ReverseConnectListener</c> singleton — multiple smoke tests in the
+///         same xunit assembly share one listener instance even if they run in
+///         parallel. Tests should pick distinct <c>ExpectedServerUri</c> values to
+///         demultiplex inbound connections.
+///     </para>
+/// </remarks>
+public sealed class OpcPlcReverseConnectFixture : IAsyncDisposable
+{
+    private const string DefaultListenerUrl = "opc.tcp://0.0.0.0:4844";
+    private const string EnvVar = "OPCUA_RC_SIM";
+
+    /// <summary>The listener URL the driver should bind for incoming reverse-connect dials.</summary>
+    public string ListenerUrl { get; } = DefaultListenerUrl;
+
+    /// <summary>Skip reason when the reverse-connect simulator isn't available; null when ready.</summary>
+    public string? SkipReason { get; }
+
+    public OpcPlcReverseConnectFixture()
+    {
+        if (string.IsNullOrWhiteSpace(Environment.GetEnvironmentVariable(EnvVar)))
+        {
+            SkipReason =
+                $"Reverse-connect smoke skipped — set {EnvVar}=1 once `docker compose -f Docker/docker-compose.yml up opc-plc-rc` is healthy. " +
+                "The dialer needs host.docker.internal to reach this machine — verify Docker Desktop's network mode supports it.";
+        }
+    }
+
+    public ValueTask DisposeAsync() => ValueTask.CompletedTask;
+}
+
+[Xunit.CollectionDefinition(Name)]
+public sealed class OpcPlcReverseConnectCollection : Xunit.ICollectionFixture<OpcPlcReverseConnectFixture>
+{
+    public const string Name = "OpcPlcReverseConnect";
+}