Try Testing Fab Apps with Vows.js

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Today, I am back on testing with vows.js. I have one last fab.js library to check, unary_try. In the application, it is used like this:

  ( /move/ )
    ( unary_try( function () {
        update_player_status(JSON.parse(""+this));
        broadcast(comet_walk_player(this));
      } ) )

When a client accesses the /move resource, the unary_try function creates a unary (upstream) application that invokes the supplied anonymous function if the downstream (browser) supplies a body / POST data. The unary_try then closes the connection with an empty response—the purpose is to update the local data store only.

First up, I test that the callback gets called:

    'with a body': {
      topic: api.fab.callback_when_send_obj({body: "foo"}),

      'invokes callback with body': function(obj) {
        assert.equal(obj, "foo");
      }
    }

That passes, but I could really use a better API test call than "callback_when_send_obj". Ick. I will leave that for now because I want to see if other calls are needed.

Next up, I want to be able to test that the downstream app gets called with empty output. That requires another vows.js topic. This time, I am not interested in verifying that the supplied callback gets called, now I want to know what the downstream (e.g. the browser gets called with), so I add to my list of API calls:

    downstream_when_send_obj: function(obj) {
      return function () {
        var topic = this;
        var upstream_listener = unary_try(
          function() {}
        ).call(
          function(obj) { topic.callback(null, obj); }
        );

        upstream_listener(obj);
      };
    }

From the top, the topic is from vows.js itself. I supply unary_try with an empty, anonymous function (again, I do not care about the callback in this case). I then call the function with a faux downstream app. Lastly, I need to send data to the upstream app which I do via the upstream_listener.

With that, I can test the response when sending data from browsers to unary_try:

    'downstream, with a body': {
      topic: api.fab.downstream_when_send_obj({body: "foo"}),
      'terminates connection': function(obj) {
        assert.isUndefined(obj);
      }
    }

After a few more of those, I have my last independent (fab) app covered:

cstrom@whitefall:~/repos/my_fab_game$ vows --spec

♢ unary_try

[unary_try] error: undefined (undefined)
  callback, with a body
    ✓ invokes callback with body
  downstream, with a body
    ✓ terminates connection
  downstream, with HTTP headers
    ✓ terminates connection
  downstream, with empty request
    ✓ terminates connection
  downstream, with exception
    ✓ terminates connection
...
✓ OK » 18 honored (0.106s)

Up tomorrow, I may clean-up / refactor these tests. Otherwise I will move onto testing some of the (fab) apps that store state.


Day #159