using System;
using System.Collections.Generic;
using System.Linq;
using NUnit.Framework;

namespace Chernobyl.Reflection
{
    /// <summary>
    /// Tests the <see cref="Utility"/> class of the Chernobyl.Reflection namespace.
    /// </summary>
    [TestFixture]
    public class UtilityTests
    {
        [Test]
        [Description("Tests the Utility.GetBaseTypes<object>() to ensure it returns " + 
            "a Type of 'typeof(object)' when the type 'Object' is passed to it.")]
        public void GetObjectBaseTypesContainsObject()
        {
            IEnumerable<Type> baseTypes = Utility.GetBaseTypes<object>();
            
            Assert.True(baseTypes.Count() == 1, "Utility.GetBaseTypes<object>() " + 
                "returned more than one Type, there should only be one: typeof(object).");

            Assert.AreEqual(typeof(object), baseTypes.First(), "Utility.GetBaseTypes<object>() " + 
                "returned a Type that is not equal to typeof(object)");
        }

        [Test]
        [Description("Tests the Utility.GetBaseTypes<object>() to ensure it returns " +
            "the proper Types for a Type whose inheritance hieararchy is more complex " + 
            "than an 'Object' type.")]
        public void GetBaseTypesReturnsProperTypes()
        {
            List<Type> baseTypes = new List<Type>(Utility.GetBaseTypes<Freshman>());

            Assert.AreEqual(baseTypes.Count, FreshmanBaseTypeCount,
                "Utility.GetBaseTypes<Freshman>() returned an IEnumerable<Type> " + 
                "that contained an expected number of Types.");

            Assert.Contains(typeof(Object), baseTypes, "List of base types did " +
                "not contain the Object type.");

            Assert.Contains(typeof(IJock), baseTypes, "List of base types did " +
                "not contain the IJock type.");

            Assert.Contains(typeof(Person), baseTypes, "List of base types did " +
                "not contain the Person type.");

            Assert.Contains(typeof(Student), baseTypes, "List of base types did " +
                "not contain the Student type.");
        }

        interface IJock { }
        class Person { }
        class Student : Person, IJock { }
        class Freshman : Student { }
        const int FreshmanBaseTypeCount = 4;
    }
}