public void TestPredicateExtensions()
{
var predicate = PredicateExtensions.And <int>(x => x > 10, x => x > 20);
Assert.IsTrue(predicate(21));
Assert.IsFalse(predicate(15));
Assert.IsFalse(predicate(5));
predicate = PredicateExtensions.Or <int>(x => x > 10, x => x < 0);
Assert.IsTrue(predicate(15));
Assert.IsTrue(predicate(-15));
Assert.IsFalse(predicate(5));
predicate = PredicateExtensions.IsNotTrue <int>(x => x == 0);
Assert.IsTrue(predicate(-1));
Assert.IsFalse(predicate(0));
}