How to use Setup method of NSpec.Tests.WhenRunningSpecs.describe_numbers class

1using FluentAssertions;
2using NUnit.Framework;
3
4namespace NSpec.Tests.WhenRunningSpecs
5{
6    public class describe_levels : when_running_specs
7    {
8        class describe_numbers : nspec
9        {
10            void method_level_context()
11            {
12                it["1 is 1"] = () => Assert.That(true, Is.True);
13
14                context["except in crazy world"] = () =>
15                {
16                    it["1 is 2"] = () => Assert.That(1, Is.EqualTo(2));
17                };
18            }
19        }
20
21        [SetUp]
22        public void Setup()
23        {
24            Run(typeof(describe_numbers));
25        }
26
27        [Test]
28        public void classes_that_directly_inherit_nspec_have_level_1()
29        {
30            TheContext("describe numbers").Level.Should().Be(1);
31        }
32
33        [Test]
34        public void method_level_contexts_have_one_level_deeper()
35        {
36            TheContext("method level context").Level.Should().Be(2);
37        }
38
39        [Test]
40        public void and_nested_contexts_one_more_deep()
41        {
42            TheContext("except in crazy world").Level.Should().Be(3);
43        }
44    }
45}

Source: describe_levels.cs

using FluentAssertions;
using NUnit.Framework;

namespace NSpec.Tests.WhenRunningSpecs
{
    public class describe_levels : when_running_specs
    {
        class describe_numbers : nspec
        {
            void method_level_context()
            {
                it["1 is 1"] = () => Assert.That(true, Is.True);

                context["except in crazy world"] = () =>
                {
                    it["1 is 2"] = () => Assert.That(1, Is.EqualTo(2));
                };
            }
        }

        [SetUp]
        public void Setup()
        {
            Run(typeof(describe_numbers));
        }

        [Test]
        public void classes_that_directly_inherit_nspec_have_level_1()
        {
            TheContext("describe numbers").Level.Should().Be(1);
        }

        [Test]
        public void method_level_contexts_have_one_level_deeper()
        {
            TheContext("method level context").Level.Should().Be(2);
        }

        [Test]
        public void and_nested_contexts_one_more_deep()
        {
            TheContext("except in crazy world").Level.Should().Be(3);
        }
    }
}