Author Archives: Ajitesh Kumar
JUnit Tests Code Samples for Testing Exception Scenarios
The article presents an example of unit tests which tests both happy path and exception scenario. Business Requirement User trying to open an account must be validated against the business rules related with users’ registration. Following are different business rules: User must provide a valid email address User must provide his first name User’s age must be 18 and above Class Design To demonstrate the unit tests with happy and exception scenarios, following classes have been shown below: SignupValidation: Consists of code validating business rules SignupException: Custom exception representing Signup business rules failure EmailValidator (Get the code from this page). SignupValidationTests: Unit tests for testing signup validation code Class …
Unit Tests – An Alternate Functional Requirements Documentation
The article presents a perspective on how unit tests could be written in a way that they could be used as an alternate form of documentation for understanding functional requirements. Many a times, it has been found that developers, primarily rookies, did not have a clarity on how to name unit tests. Thus, many of them have been found to name the unit tests such as testXXX where XXX is name of the method which they wanted to tests. There has been many recommendations on how to name unit tests, some of which are following: Given…When…Then… Check the page by Martin Fowler (http://martinfowler.com/bliki/GivenWhenThen.html) WhenXXX_ExpectYYY Names representing different use case scenarios …
Content Framework for Lunch & Learn Sessions on IT Applications
The article represents a framework using which one could plan their content for taking an introductory session on their applications. The primary objective of such presentation is to provide the audience with following information: Business overview Applications overview The proposed framework aims to satisfy the education needs for different stakeholders including delivery manager, project manager, development & testing teams. Presenters talked differently In my recent experience, I attended a series of sessions taken by leads of different project teams working for the same customer. Except for few of them, most of these sessions were not very interesting and audience enjoyed lunches more than the sessions. Following are some of the …
APIs Performance Testing with Twitter Iago
The article talks about performance testing tool, Iago, which is created at Twitter for testing their core database interfaces, storage sub-systems and domain logic, up to the systems accepting front end web requests. Performance requirement of Twitter platform? Simply speaking, end users expect to read & post tweets with a very fast response time and, Twitter is expected to respond in that manner irrespective of load arriving at it with absolutely no room for any slowness, whatsoever. That is a tough one, isn’t it? This is unlike many enterprise business systems where users can be a little forgiving by waiting for the response to show up. So, they needed to …
Mobile Apps Testing Frameworks Used at LinkedIn
The article lists down tools & frameworks that are used for mobile app testing at LinkedIn. Vows: Vows is a behavior driven development framework for Node.js. It is used to do asynchronous testing with Node.js. The primary feature of the framework is its support for asynchronous testing with Node and, the ability to run concurrent tests. Vows also supports code coverage reporting. Robotium: Robotium is an Android test automation framework that has full support for native and hybrid applications. It supports black-box UI tests for android applications. It is used to test native LinkedIn android app. Selenium: Selenium is used to automate end-to-end testing with mobile web browsers. FoneMonkey: FoneMonkey …
How to Measure Software Development Productivity
The article lists down pages/papers on measuring software development productivity. The Theory of Constraints: A good read on measuring software development productivity Measuring Productivity of Software Development Teams: The paper lists down different techniques/models for measuring software development productivity. CannotMeasureProductivity: Then, there is this article by Martin Fowler which says that it is difficult to measure software development productivity. He points about ineffectiveness of following approaches of measuring developer’s productivity: Lines of codes (LOC) Function points The software development teams working based on Waterfall model or Agile methodologies model tend to measure the developer’s productivity in terms of following variants: Function Points Story Points (size) vs Velocity Following pages present …
List of Javascript Templating Engines & Why One Needs Them?
The article presents a short overview on why one needs Javascript templating engines and, a list of these frameworks. Please feel free to suggest one or more frameworks if I missed to include them in the list below. Why do I ever need Javascript templating engine? Consider the following use-case scenario. Let’s say, you are a big enterprise with different line of businesses (LOBs). Each LOB has a set of web applications serving its business needs. With different LOB having different applications, following scenario is likely to happen: One particular LOB, X, has applications written with Java/JSP. Other LOB, Y, has applications written with .NET technology Other LOB, Z, …
Why Facebook Relies on A/B Testing?
This article talks about A/B testing, why companies like Facebook rely on it and what would it take to adopt such testing for your website. What is A/B testing? A/B testing is a strategy in marketing in which two versions, A and B, (the control and the treatment) are tested against each other. A/B testing, as the names implies, is a simple randomized experiment with two variants/versions, A and B, one of which version A might be currently used version (control) and, version B (treatment) is modified in some respect to study/test the users’ behavior. These tests are also called as split tests. These tests involve modification some of the following …
Lessons from Evernote Usage of Apache Thrift Framework
This article throws light on underlying technology used by Evernote to meet the primary requirement of having client applications on different OS platforms connect to server application for accessing/updating the notes. What is Evernote? As per Wikipedia…Evernote is a suite of software and services designed for notetaking and archiving. A “note” can be a piece of formatted text, a full webpage or webpage excerpt, a photograph, a voice memo, or a handwritten “ink” note…. Evernote supports a number of operating system platforms (including OS X, iOS, Chrome OS, Android, Microsoft Windows, Windows Phone, BlackBerry, and webOS) and also offers online synchronisation and backup services. The diagram below illustrates …
Why Amazon.com Pages Rely on DNS Pre-fetch
The article presents a perspective on why Amazon.com pages rely on DNS pre-fetch and what other e-commerce websites could learn from this. Whats Happening Under the Hood? As you do the view source of the homepage, amazon.com, you would find following Javascript code snippet, right at the top of the page: <meta http-equiv=”x-dns-prefetch-control” content=”on”> <link rel=”dns-prefetch” href=”http://g-ecx.images-amazon.com”> <link rel=”dns-prefetch” href=”http://z-ecx.images-amazon.com”> <link rel=”dns-prefetch” href=”http://ecx.images-amazon.com”> <link rel=”dns-prefetch” href=”http://completion.amazon.com”> <link rel=”dns-prefetch” href=”http://fls-na.amazon.com”> Later, in the same page as well as other pages, you would find several resources such as images, Javascript, CSS files accessed from one of the above as base URLs. So, let’s try and explore some of the …
Javascript Frameworks used in LinkedIn.com
The article lists down different Javascript frameworks that have been used in LinkedIn web UI and mobile app. Following are some of the key Javascript frameworks that have been used in various different LinkedIn applications (Web & Mobile). If you disagree with one or more of these frameworks, please shout out loud. Also, feel free to suggest of frameworks that I missed to include. Sorry for any typos/misspellings as you read further. Dust.js Dust.js, the client-side templating engine, is used to serve LinkedIn webpages with common UI code for different web-apps products. These web-apps products are created using varied technology stack including Java/Grails/JRuby etc. With Dust.js, LinkedIn moved from …
LinkedIn Application Architecture – Software Distribution View
The article lists down the softwares used at different layers in the LinkedIn platform layered architecture. Presentation Layer Dust.js (Client-side templating JS engine) Backbone.js (Client-side MVC JS framework) JQuery YUI Library (UI libraries started by Yahoo engineers) Google V8 Engine (Used as server side JS templating engine) Node.js (Used in mobile app) HTML5 (Used in mobile app) Business Layer Java (Applications such as Profile) Grails (Applications such as a Recruiter app) JRuby (Applications such as a Skills app) Spring (Component Model) Scala Middleware Apache Kafka (Distributed entreprise-level messaging system) Data Layer Oracle (RDBMS as primary data store used for writes) Espresso (NoSQL data store emerging as primary data store and envisioned to …
OWASP Security Misconfiguration Example – Infosys Career Website
The article presents an example of “Security Misconfiguration” vulnerability that was found on Infosys career website. It could be noted that security misconfiguration is considered as one of the OWASP top 10 security vulnerabilities. The vulnerability was found with Careers web application of Infosys, which can be accessed at https://careers.infosys.com/. As you access the career site link, you would see the title icon as “SAP”. This does suggest that Infosys careers web application is created on top of SAP career module. The way I found that is following: Go to job opportunities page. Click on “Register”. You would land on the registration page with following link: https://careers.infosys.com/sap/bc/webdynpro/sap/hrrcf_a_candidate_registration Go ahead and strip the hrrcf_a_candidate_registration from …
Data Architecture Lessons from LinkedIn.com Data Handling Mechanisms
The article aims to describe how data is managed at LinkedIn.com, the most popular professional social networking site. Please shout out loud if you disagree with one or more of the aspects mentioned below. Also, do suggest if I missed on one or more aspects. Data use-cases at LinkedIn.com Following are some of the data use-cases that we may have come across while we are surfing various different LinkedIn pages: Update your profile, and the same appears in recruiter search in near real-time. Update your profile and same appears as network connections in near real-time. Share an update, and same appears on others news feed page in near real-time. Then, there are …
Reasons Why You Need Log Management Tools like SPLUNK
The article lists down reasons why one would want to use tools such as Splunk which primarily analyses logs (server, application etc) and create reports/events to be processed by different stakeholders. Log Management Tools – High Level Architecture Log management tools primarily aggregate logs from different servers including application, database, messaging servers etc and send the same to a centralized server which then analyzes and index the logs in the database. The end user can then log onto the console of these tools and analyze the reports created on top of these logs. Following diagram represents a very high level architecture along with end users classification: Following are some of …
Developers Playgrounds to Play & Learn
The article lists down the details around different programming playgrounds that could be used by developers to learn while playing with different technologies (programming languages & APIs). What are Developers Playground? Developers playground are online applications that facilitates enhanced learning of different programming languages/API by providing developers with the IDEs like development platforms where different programs could be written and executed side-by-side and results could be studied/examined. Following is the broad classification of such playgrounds. Programming Playground In playgrounds related with programming languages, developers could learn languages while doing the coding and see the output side-by-side. Following are some of the programming playgrounds: Codecademy.com (It also presents playground for APIs …
I found it very helpful. However the differences are not too understandable for me