using UnitTestSharp;

namespace Vellum.UnitTests
{
    public class ReferenceComparerTests : TestFixture
    {
        public class EqualsTests : TestFixture
        {
            public void SameObject_IsEqual()
            {
                var stamp = new Stamp { Id = "a" };

                CheckTrue(ReferenceComparer.Instance.Equals(stamp, stamp));
            }

            public void EqualButDistinctObjects_AreNotEqual()
            {
                CheckFalse(ReferenceComparer.Instance.Equals(new Stamp { Id = "a" }, new Stamp { Id = "a" }));
            }

            public void Strings_AreComparedByIdentityToo()
            {
                string first = new string('a', 3);
                string second = new string('a', 3);

                CheckFalse(ReferenceComparer.Instance.Equals(first, second));
            }

            public void TwoNulls_AreEqual()
            {
                CheckTrue(ReferenceComparer.Instance.Equals(null, null));
            }
        }

        public class GetHashCodeTests : TestFixture
        {
            public void SameObject_HasTheSameHashCode()
            {
                var stamp = new Stamp { Id = "a" };

                int first = ReferenceComparer.Instance.GetHashCode(stamp);

                CheckEqual(first, ReferenceComparer.Instance.GetHashCode(stamp));
            }

            public void ObjectOverridingGetHashCode_IsHashedByIdentity()
            {
                var stamp = new Stamp { Id = "a" };
                int before = ReferenceComparer.Instance.GetHashCode(stamp);
                stamp.Id = "b";

                CheckEqual(before, ReferenceComparer.Instance.GetHashCode(stamp));
            }
        }
    }
}