fix(commons): resolve Commons-001..004 — stale-fire race, JsonDocument lifetime, GetNullable strictness, registry symmetry

tests/ScadaLink.Commons.Tests/Messages/ManagementCommandRegistryTests.cs

@@ -0,0 +1,78 @@
+using System.Reflection;
+using ScadaLink.Commons.Messages.Management;
+
+namespace ScadaLink.Commons.Tests.Messages;
+
+/// <summary>
+/// Tests for <see cref="ManagementCommandRegistry"/>, including the Commons-004
+/// regression: <c>GetCommandName</c> and <c>Resolve</c> must be symmetric — every
+/// type for which <c>GetCommandName</c> yields a name must round-trip back to the
+/// same type via <c>Resolve</c>.
+/// </summary>
+public class ManagementCommandRegistryTests
+{
+    private static IEnumerable<Type> RegisteredCommandTypes() =>
+        typeof(ManagementEnvelope).Assembly.GetTypes()
+            .Where(t => t.Namespace == typeof(ManagementEnvelope).Namespace
+                        && t.Name.EndsWith("Command", StringComparison.Ordinal)
+                        && !t.IsAbstract);
+
+    [Fact]
+    public void GetCommandName_Resolve_RoundTrips_ForEveryRegisteredCommand()
+    {
+        foreach (var type in RegisteredCommandTypes())
+        {
+            var name = ManagementCommandRegistry.GetCommandName(type);
+            var resolved = ManagementCommandRegistry.Resolve(name);
+            Assert.Equal(type, resolved);
+        }
+    }
+
+    [Fact]
+    public void Resolve_KnownCommand_ReturnsType()
+    {
+        var type = ManagementCommandRegistry.Resolve("CreateSite");
+        Assert.Equal(typeof(CreateSiteCommand), type);
+    }
+
+    [Fact]
+    public void Resolve_UnknownCommand_ReturnsNull()
+    {
+        Assert.Null(ManagementCommandRegistry.Resolve("NoSuchCommand"));
+    }
+
+    [Fact]
+    public void Resolve_IsCaseInsensitive()
+    {
+        Assert.Equal(typeof(CreateSiteCommand), ManagementCommandRegistry.Resolve("createsite"));
+    }
+
+    /// <summary>
+    /// Commons-004: <c>GetCommandName</c> previously stripped a <c>Command</c> suffix
+    /// from <em>any</em> type, producing names the registry cannot resolve. It must
+    /// only return a name for a command type the registry actually contains.
+    /// </summary>
+    [Fact]
+    public void GetCommandName_UnregisteredCommandType_Throws()
+    {
+        // A *Command type that is not in the Messages.Management namespace.
+        Assert.Throws<ArgumentException>(
+            () => ManagementCommandRegistry.GetCommandName(typeof(UnregisteredFakeCommand)));
+    }
+
+    [Fact]
+    public void GetCommandName_NonCommandType_Throws()
+    {
+        Assert.Throws<ArgumentException>(
+            () => ManagementCommandRegistry.GetCommandName(typeof(string)));
+    }
+
+    [Fact]
+    public void GetCommandName_RegisteredCommand_ReturnsStrippedName()
+    {
+        Assert.Equal("CreateSite", ManagementCommandRegistry.GetCommandName(typeof(CreateSiteCommand)));
+    }
+
+    /// <summary>A *Command record outside the Management namespace, for the negative test.</summary>
+    private record UnregisteredFakeCommand(int Id);
+}