Using BrowserScope to Detect Geolocation Support

About Browserscope

Browserscope is a very cool tool coming out of Steve Souders’ performance efforts and being developed by Steve along with Lindsey Simon. It’s part of a trend towards crowdsourcing browser info, in similar vein to TestSwarm, for testing specific code, and along the lines of what I did with WebWait, which is to support multiple people benchmarking a website at once. (Though I’ve not set up reporting on it – one day…)

So anyway, Browserscope began life as a way to benchmark just performance, but is now a general-purpose tool for crowdsourcing tests about anything browsers do, e.g. checking for security vulnerabilities is one vital application. HTML5 does not miss out – has been ported over too – see

Geolocation Test

I decided to make my own test recently, to see what extent Geolocation is being supported by the browsers. Run the test against your browser here (it will upload only information about whether geo is supported, not your actual geolocation data):

The results so far indicate browsers either don’t support it, or support accuracy+lat+lon. I was hoping to see at least direction, and would <3 to see altitude! But it will have to wait.

How to Make your Own Browserscope Test

If you ever wanted to know how every browser under the sun handles a particular something, Browserscope is your new hotness. It makes it trivial. Register with Browserscope to get the boilerplate code. Then you just write an app that does the exercises and builds up a hashmap of the info you want to collect, and BAM, submit it. The hashmap should have values between 1 and 1000. Do that, and you’ll end up with a nice summary page showing your test results aggregated across all browsers that ran them.

The submission is taken care of by some boilerplate code – it uses on-demand Javascript to pass the data back to the third-party BrowserScope domain (you host the test yourself). Aside from writing the actual test and promoting its location, the only thing you have to do is make a nice UI to show the users what you just did, and perhaps get their consent before uploading. I think those are actually two things Browserscope could automate too, at least providing a nice default UI which test creators can customise.

8 New Ajax Patterns (Diagnosis and Testing)

Cool! The Best Practices/Processes Patterns are now complete. They are the final eight Ajax Patterns for now – “final” in the sense of “the list is not yet finalised”. The patterns had been sitting there unattended for about four months now.

More details on the new patterns later, but here’s a quick summary …

First, there’s a new demo – the Ajax Patterns Reader – the best version to try is at The reader grabs the content and presents them Ajax-style. You actually queue up patterns in a playlist and click “Next” to “play” them. Yeah, a bit contrived, but it helped illustrate quite a few patterns! If I have time, I’d like to enhance it into a proper reader, and also offer an easy interface to leave feedback, which would be automatically appended to the wiki’s Discussion tab for that pattern.

BTW This further refactoring of the Ajax Patterns Reader illustrates the Scriptaculous GhostTrain tool. If you haven’t seen GhostTrain, have a look – the Javascript will track your activity and build up a test case dynamically (covered in the new System Test pattern). All within the browser. I’ve been in contact with the developers (Thomas and Jon), and discovered it’s still proof-of-concept, but if they can tie it all together, it will be an excellent way to create a system/functional test.

Next, there’s four patterns on diagnosis:

And finally, four patterns on testing:
  • Simulation Service Develop the browser application against “fake” web services that simulate the actual services used in production.
  • Browser-Side Test Create automated tests of browser-side Javascript components.
  • Service Test Build up automated tests of web services, using HTTP clients to interact with the server as the browser normally would.
  • System Test Build automated tests to simulate user behaviour and verify the results.

Mocks, Stubs, Dependency Injection, and … XMLHttpRequest

“A Mock Is Not So Stupid After All!”

Dave Crane’s been talking about Mocking the Server-Side:

A Mock Object is a stand-in for the real thing. Few modern programs are really standalone, and enterprise apps require a very complex context in order to operate; containers, databases, directories, web services, etc. This can make testing difficult, because to set up the test and run it, one needs to provide all the necessary context. Mock objects can be thought of as really dumb implementations of a contextual element, one that would never be useful in production, but provides the predictability and ease of setup required for a test. A mock database might always return the same four rows of data, whatever the WHERE clause. A mock web service might always serve up the same XML document.

So the idea is to create a simulation XML document (or plain-text document) to be retrieved with XMLHttpRequest.

Dave’s followed up with some good tips to that end. All good timing as I’ve recently been working on a demo for the final lot of patterns – the process patterns – and one of the refactorings uses a canned plain-text document to illustrate The Pattern Currently Known As “Server-Side Simulation Stubs” (who said alliteration had no place in software writing?).

Worth noting the terminology used, and here I’ll be pedantic. Dave refers to a Mock what I call a Simulation Stub. In the past couple of years, the terms “Mock” and “Stub” have often been used interchangeably, but I think the distinction is worth keeping, because otherwise the original meaning of Mocks is lost. I don’t really care what things are called, but when two concepts become one name, at least one of those concepts is going to get hurt. It’s a testament to the creators of Mocks that they managed to produce a name so evocative that it’s come to consume a much older concept. (“Stub” and “Shunt” have always been pretty vague terms anyway.)

Under the original definition, a Mock is an object that verifies how it’s being used by a tested object, and by inference, how things like it will be used by the class being tested. Yes, it might spit out simulation data, and it might even have a fancy interface that lets you tell it how to respond. However, those functions are only there to help verify how it’s used. It’s what goes into the mock that counts, not what the mock pumps out. Corollary: a Mock is not stupid. It might not win a Nobel Prize anytime soon, but it’s smart enough to know what to expect and how to check if that expectation’s been met. The mixing of terms has carried over to some parts of the Ruby/Rails community, as Aslak recently observed during a RubyConf presentation. (Podcast on mocks, Fowler’s Mocks Aren’t Stubs.)

In a web context, what might the distinction mean?

  • A Simulation Web Service (or a “Stub Web Service”, but I prefer “Simulation”) is typically some XML or plain-text document that’s been written manually. It could also be a bit more sophisticated, offering a means for the server-side developer to tweak its output.
  • A Mock Web Service is a server-side script that’s been configured to expect a certain sequence of XMLHttpRequest messages, and will carp as soon as the sequence is broken.

As Dave’s articles explain, a Stub Web Service is certainly a useful thing, and I suspect quite a few developers follow that practice. (Please tell me about it if you do!)So how about Mock Web Services? That’s pure speculation!! I could see the benefit, but I’ve not done it, haven’t heard of anyone doing it, and I seriously doubt there are any frameworks that facilitate it.

A variation on Simulations and Mocks would be a completely browser-side approach, in which you adopt an XMLHttpRequest wrapper, and make it output a dummy document while in “testing” mode. This raises further questions:

  • How are mocks handled in Javascript? Well, William Taysom recently noted that you can approximate method_missing, and a Mock library like the awesomely useful JMock library is clearly feasible. There are a few JUnit equivalents out there, so why not a mock lib? (Would you use such a thing?) If you say that would be over-engineering, then the same charge could be made about JS testing in general, since mocks are really a natural consequence of unit testing and TDD … any time you find yourself testing an event mechanism, a mock might be a good idea.
  • How to switch context in Javascript? Okay, so mocks are a big reason for the rise of Dependency Injection and “lightweight” (( containers in Java/J2EE/JEEWhiz. Well then, doesn’t Javascript need the same thing? Again, I know, “you’re over-engineering it, Mahemoff”. So maybe I am. It’s been said that Dependency Injection doesn’t do much for Ruby, and maybe the same’s true for JS. So how then, do you make your browser app switch between a mock web service and a production service? The answer is not, “change the source code”, because to achieve continuous integration, you want to keep an automated test around that calls the mock service. Maybe the best thing to do is rely on DI – or some other context-switch mechanism – in the server, so that the Javascript that it spits out will differ according to the environment.