feat(auditlog): scaffold ScadaLink.AuditLog project + tests project (#23)

tests/ScadaLink.AuditLog.Tests/AddAuditLogTests.cs

@@ -0,0 +1,50 @@
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Options;
+using ScadaLink.AuditLog.Configuration;
+
+namespace ScadaLink.AuditLog.Tests;
+
+/// <summary>
+/// Bundle E (M1) smoke tests for the Audit Log (#23) DI scaffold. Verifies
+/// <c>AddAuditLog</c> registers <see cref="AuditLogOptions"/> against the
+/// <c>AuditLog</c> configuration section. Bundle E ships only the scaffold;
+/// the validator + full options surface land in Task 9.
+/// </summary>
+public class AddAuditLogTests
+{
+    [Fact]
+    public void AddAuditLog_RegistersAuditLogOptions()
+    {
+        var config = new ConfigurationBuilder()
+            .AddInMemoryCollection(new Dictionary<string, string?>())
+            .Build();
+
+        var services = new ServiceCollection();
+        services.AddAuditLog(config);
+        var provider = services.BuildServiceProvider();
+
+        var opts = provider.GetService<IOptions<AuditLogOptions>>();
+
+        Assert.NotNull(opts);
+        Assert.NotNull(opts!.Value);
+    }
+
+    [Fact]
+    public void AddAuditLog_NullServices_Throws()
+    {
+        var config = new ConfigurationBuilder().Build();
+
+        Assert.Throws<ArgumentNullException>(
+            () => ServiceCollectionExtensions.AddAuditLog(null!, config));
+    }
+
+    [Fact]
+    public void AddAuditLog_NullConfig_Throws()
+    {
+        var services = new ServiceCollection();
+
+        Assert.Throws<ArgumentNullException>(
+            () => services.AddAuditLog(null!));
+    }
+}