public void Test_is_symmetric()
{
var binaryRelation = new Set<Tuple<int, int>> { new Tuple<int, int>(1, 1), new Tuple<int, int>(1, 2) };
binaryRelation.IsSymmetric().ShouldBeFalse();
binaryRelation.Add(new Tuple<int, int>(2, 1));
binaryRelation.IsSymmetric().ShouldBeTrue();
binaryRelation.IsEquivalenceRelation().ShouldBeFalse();
}
