return handler in reply(...) mocks in order to allow removing handler and monitoring calls

[burgalon]

Similarly to WebMock it would be nice if mocking replies will return the handler so that later we can:

1. Assert that mock has been called
2. Remove handler if necessary

[ctimmerm]

Thanks for your pull request!
I agree that this would be a useful feature, but if the handler is returned from reply it would mean quite a large breaking change is introduced (any existing code that uses chaining would no longer work). Maybe it could instead be done in a way that is backwards compatible by adding an extra method? Something like:

var handler = mock.onGet(...).reply(...).handler();

[burgalon]

Hey Colin,
The suggestion .handler() doesn't seem quite right: That would mean that we we would need to save the last handler in _this and then .handler() would return it?
More generally, I think it would be nice if we take axios-mock-adapter further in the direction of not jus mocking, but also allowing matchers and assertions for requests which have occured like WebMock. Thus I think letting go of chaining, is for a good cause :)

[ctimmerm]

What if we could have the best of both worlds and instead of returning either the instance or the handler, return a proxy that proxies the methods/properties to either the instance or the handler.

A contrived example:

function createProxy(instance, handler) {
  var proxy = {
    handler: handler,
    instance: instance,

    get: function() {
      return instance.get.apply(instance, arguments);
    }
  };

  Object.defineProperty(proxy, 'called', {
    get: function() {
      return handler.called;
    },

    set: function(value) {
      handler.called = value;
    }
  });

  return proxy;
}

[burgalon]

personally I like when things are straight forward, and the object type at hand is of clear type and interface. The suggested proxy makes it harder to follow the code and understand

[burgalon]

we could have a flag at the mock level determining what's the returned object... but that will create communities forking usage instead of forked code :)