Add test case for bug 340

src/Lamar.Testing/Bugs/Bug_340_open_generic_interface_registration_check.cs

@@ -0,0 +1,30 @@
+using Shouldly;
+using Xunit;
+
+namespace Lamar.Testing.Bugs;
+
+public class Bug_340_open_generic_interface_registration_check
+{
+    class ClassA {}
+
+    interface IGenericService<T> {}
+
+    class ServiceA : IGenericService<ClassA> {}
+
+    [Fact]
+    public void Test_it()
+    {
+        var container = new Container(x =>
+        {
+            x.For<IGenericService<ClassA>>().Use<ServiceA>();
+        });
+
+        var x = container.GetInstance<IGenericService<ClassA>>();
+
+        container.GetInstance<IGenericService<ClassA>>()
+            .ShouldNotBeNull();
+
+        container.Model.HasRegistrationFor(typeof(IGenericService<>))
+            .ShouldBeTrue();
+    }
+}