The Art of Data Aggregation: Personal Capital @ FinDevR 2014

On September 30, Personal Capital presented at the inaugural FinDevR conference in San Francisco. FinDevR, a spinoff of the successful Finovate conference, is oriented to developers and technologists in the very robust financial technology (aka fintech) space. The conference sponsorship was dominated by some well-known household names, such as MasterCard, Paypal, Intuit, and TD Ameritrade, as well as lesser-known (but prominent in fintech) companies such as Yodlee and XIgnite.

In addition to the big players there, there were plenty of emerging entrepreneurs there among the 40+ sponsors and presenters, and it was a great chance to talk tech, rather than business models and user acquisition, with some smart people that were out showcasing great ideas. Payment technology was a big theme at the conference, as well as small-business and micro-lending; social/community angles on financial domain;  big data (always), and lots more. Several companies were there launching new platforms and service, such as Finicity’s account aggregation platform, and Kabbage’s Karrot lending platform for individuals.  It was a well-organized event, especially considering that this was the first time it had been offered, and organizers said there were over 400 attendees.  (CES it is not, and thank goodness for that).

Ehsan and I presented a talk there for developers, “The Art of Data Aggregation”, sharing some of our ideas for financial data aggregation, the foundation for data-intensive fintech services and applications. While most of the other presenters were there pitching their b2b services for fintech developers, we got to relax and just share a purely technical talk, without the added burden of needing to sell anything. (OK, *fine*, we did mention that Personal Capital helps over 600,000 people manage over $100 billion in assets.  I actually don’t really get tired of saying that).  If you’re interested in watching a video of our 6-minute presentation, or any other the presentations, check it out.

Automate E2E Testing with Javascript


  • Faster delivery of software
  • Set us on the path of Continuos Delivery
  • Immediate discovery of regression
  • And why javascript – Facilitate front-end team to actively contribute to tests alongside feature development


  • Build an automation framework which will simulate user interactions, and run these tests consistently on real and headless browsers alike
  • Set up integration with CI server(Jenkins)
  • Import test results into our Test Management Platform(QMetry)


The front-end team uses Mocha/Chai/Karma for writing unit tests. The QA team uses Selenium for automation. When we picked these frameworks and tools, we evaluated them thoroughly for our needs. We also wanted to leverage our existing frameworks and tools as much as we could so that there would be less of a learning curve. Fortunately for us, we found Selenium bindings in Javascript. Actually there are quite a few, but the most prominent of them are and Selenium’s webdriverJs.

We chose Selenium’s webdriverJs primarily for the following reasons:

  • It is the official implementation by the Selenium team who have written bindings in various other languages
  • The patterns of writing a test is very similar to a test written in java world with which our QA team was familiar
  • Its use of promises to prevent callback hell

For more detailed explanation with examples, please refer here.

Our next piece of the puzzle was to figure out if we could use PhantomJs (headless browser) with webdriverJs. We needed this so that we could run the tests on our CI server where we may not necessarily have a real browser. We did have some initial challenges to run webdriverJs in combination with PhantomJs without using Selenium’s Remote Control Server, but looking at the source code (in Javascript) helped us debug and get this to work. The challenges could also be attributed to the lack of complete understanding of Selenium’s automation world.

The last piece of the puzzle was integration with the CI server. With PhantomJs already in place, all we needed to figure out was the reporting format of the tests that our CI server (Jenkins) could understand. One of the reasons we had picked Mocha is for its extensive reporting capabilities. Xunit was the obvious choice because of Jenkins support for it.

And there it is – our automation framework – all of it in Javascript stack.

Testing Stack for Web

In the past couple months, we have successfully automated our E2E tests that provide coverage for regression of our web platform, and use it on a daily basis. Now that we have an established framework and gained immense experience writing tests, we are one step closer to Continuous Delivery. Integration with our Test Management Platform is in the works and we will post our findings soon.


Web Automation Testing v2

I grew up on the east coast, currently go to school in the midwest, and was fortunate enough to spend my summer on the west coast working with the Personal Capital engineering team. In addition to working on an amazing engineering team, I became familiar with the workings of a fast paced tech environment and learned a great deal about web and mobile automation. Javascript is now my strongest programming language, and I learned to appreciate its value to a commercial company (not just a coding assignment). I could have not asked for a better summer experience.

My coworker, Nick Fong, already wrote a post here describing the main points of our project this summer. So as to not be repetitive, I will be writing more about the problems and road blocks we faced along the way and how we overcame them. I highly suggest reading his post first to get a better idea of the general framework that I will be talking about. You can Nick’s post here.

Working with selenium WebDriverJS, there were many concepts that were new to me, but Javasript promises and how they worked in an asynchronous fashion, were one of the most confusing. First, promises were necessary for the scripts we wrote because they were the only way to access information from the driver. Below is an example of using a promise to access the pin field while linking accounts. In this piece of code, it is verifying that a pin field is there by checking if the information returned by the driver is not null.

driver.findElements(webdriver.By.css('[name="PASSWORD1"]')).then(function(pin) { 
    var length = pin.length; 
    if (pin.length > 0) { //makes sure the pin location is there 
        helper.enterInput('[name="PASSWORD1"]', accounts['L'+index].v); // Name distinct for Firstrade 

This in itself was not that difficult to do in our scripts. We created many ‘helper’ functions, which you can see used above, that use promises to access and manipulate the driver. What took some time to grasp was in asynchronous scripts; anything that happens within the promise stays within that promise. This turned into a scoping issue when I would edit global variables inside the promise and have another promise read the original value of this variable.

For the builds to pass, the scripts must run in PhantomJS, a headless browser we ran everything on before pushing to productions, with no errors. However, just because it worked on PhantomJS did not mean it would work on the other browsers. We found after much trial and error that PhantomJS behaved the most like Safari, but this did not guarantee a script working in Safari would work in PhantomJS. A very peculiar error I faced occurred when writing automation scripts for in chrome. When I was testing the links on the page, everyone but the last one would fail and for the longest time I had no idea why. Eventually I figured out that the banner that followed the user down the page when he/she scrolled was blocking the link because our code would scroll so the link was the closest to x:0 y:0 before clicking. To change this:

driver.executeScript(‘window.scrollTo(0,’ + loc.y + ‘)’);
was changed to this:
driver.executeScript(‘window.scrollTo(0,’ + loc.y-50 + ‘)’);

This change, although extremely simple, took a long time to figure out. It also gave me a greater appreciation for this work and how much time it actually takes. Before working here, I would, like most developers, spend a lot of time debugging my code. Only after working for a company that is actually pushing a product out to a customer did I truly appreciate the time needed to get everything right.

I divided all the tests into two categories: tests that were completely internal and that that used outside information. Internal test would be something like checking to make sure our information gathering survey worked or that the marketing page’s links were working. The latter type consisted of such tests as linking accounts or checking transactions. One of the tests I wrote contained a script for added accounts to test IDs and checked to make sure everything was linked correctly. Not only did the parameters of this test change three times, thanks guys, but also I had to deal with naming conventions that were out of our control. For the most part, they were consistent for username and password, but when other fields were added, all bets were off.

Although I joked about the changing of parameters, it actually was an important part of my summer because it exposed me to the compromises that automation scripts need to accommodate. The debate was how dynamic the script would be. Obviously, in an ideal world, the script could link any account in any way. However, after a lot of work, and because we had to rely on third party information, this was not possible. So the question remained whether we wanted a smoother, simpler script that tests the basic functionality for a few accounts, or tries our best to be fully dynamic. Eventually we decided on the former, setting aside five accounts of different types to aggregate.

There is so much more I could talk about, but that is for another time. I would recommend using Selenium WebdriverJS, found here, for writing these automation scripts to anyone who might be interested. I want to thank all the people at personal capital for making me feel at home this summer; it was a pleasure coding with you.