public void Handler()
{
var ctx = new Context();
var handler = new Handler <Context>(1, _ctx => _ctx.counter++);
// The handler is added through the Add method
var chain = new Chain <Context> {
handler
};
Assert.That(chain.Contains(handler));
// The handler remains after a pass
// It also gets executed
chain.Pass(ctx);
Assert.That(chain.Contains(handler));
Assert.AreEqual(1, ctx.counter);
// The second handler overrides the first handler
// Since it is executed after that, setting the value to 5
var handler2 = new Handler <Context>(2, _ctx => _ctx.counter = 5);
chain.Add(handler2);
chain.Pass(ctx);
Assert.That(chain.Contains(handler2));
Assert.AreEqual(5, ctx.counter);
// Removing a handler works
// The previous handler is the only one executing, incrementing the value
chain.Remove(handler2);
Assert.False(chain.Contains(handler2));
chain.Pass(ctx);
Assert.AreEqual(6, ctx.counter);
// If you were to stop propagation, the value will not be incremented
var handler3 = new Handler <Context>(0, _ctx => _ctx.Propagate = false);
chain.Add(handler3);
chain.PassWithPropagationChecking(ctx);
Assert.AreEqual(6, ctx.counter);
// Removing all handlers
chain.Clear();
// You may also remove a handler while a pass is being made
// This is achieved by creating a copy of the array with handlers before iterating.
// There are better ways to do it, which I'll propably get to later,
// if these copies become a problem.
var handler5 = new Handler <Context>(5, _ctx => _ctx.counter = 9);
var handler4 = new Handler <Context>(4, _ctx => chain.Remove(handler5));
chain.AddMany(handler4, handler5);
ctx.Propagate = true;
chain.PassWithPropagationChecking(ctx);
Assert.AreEqual(9, ctx.counter);
ctx.counter = 69;
chain.PassWithPropagationChecking(ctx);
Assert.AreEqual(69, ctx.counter);
}