Today I am looking at another design pattern. This one is the command design pattern, which is yet another Gang of Four design. They classify it as a behavioral pattern with object as the scope (GoF 223). I wanted to explore this one as reading through the different pattern descriptions in the Gang of Four book, this peaked my interested by its ability to separate requests from objects. The article gives a good summary of the idea of the pattern with a real-life example of a restaurant with a server taking an order from a customer and handing it off to a chef. It then further breaks down the pattern with the usual UML diagram and a helpful sequence diagram that shows the order in which the classes perform the pattern. I found this sequence diagram, along with the comments in the example program with code that show which class matches with which part of the diagrams really useful in this example, as the pattern goes through a couple of classes just to call a basic function on a simple object. Although this pattern does seem complex at first, it has a nice simplicity once you understand what all the classes are doing, and once you get the base created adding more functions is as simple as adding more command classes. The article then creates a simple example with Java of the command pattern using the various classes to switch a light bulb object on and off. I do like the idea of the pattern and its particular implementation in this example. It nicely breaks down requests into their own separate command objects that gives much greater control over requests across a program. I agree that the ability this pattern gives to create a log of function calls and add an ability to undo all functions called on an object is very helpful. I also agree with the author that it can get messy if you have a lot of functions that need to be implemented. As this pattern calls for a separate command class to be made for each function or method performed on an object, this can quickly add up depending on how many methods you need in your program. In the future, I will definitely remember this pattern and its useful ability to separate commands from the objects it performs them on.

Source: https://dzone.com/articles/design-patterns-command

 

From the blog CS@Worcester – Chris' Computer Science Blog by cradkowski and used with permission of the author. All other rights reserved by the author.

For my last blog for this class — Software Quality Assurance and Testing — I decided to look at what I could find about the subject in the news. After searching around, I found an article from Forbes that came out only a few days ago — December 17. The article was titled “AI In Software Testing: Will A Bot Steal Your Spot?”

My first impression before I read the article was, “Of course not! There will always be people whose job it is to test software.” Software is growing to touch every corner of our lives, and even if AI is incorporated, I would think it would be unlikely that they would entirely, or even partially, replace testers.

Halfway through the article, the author confirmed my skepticism by saying, “While it’s unlikely the testers will be wiped out, I think machine learning and other branches of AI will significantly alter the way software testing is conducted.”

The article seems to have a misleading title. The article goes on to give several examples of how robots will be useful for people, but they will be still be implemented by people, whose jobs are still be there, even with the robots. It didn’t even hint even some jobs would be lost. It just said the job would look different. Seems pretty obvious that new tools will come out that will change how the work is done. That is true for most all industries.

The article might as well been titled “Sharks in the Ocean: Will You Be Eaten When You Go Swimming?” And then once you read it says “probably not.” This is link bait at it’s finest. Have a sensationalized title for people to click on, and then say, “It’s not going to happen.” It would be one thing if it were titled something different.

However, at least I sighed a breath of relief when I read what the article concluded. I would hate for something that I have wanted to pursue as a career be automated before I even graduate.

I’m sure that many parts of the computer science industry that will change dramatically over my career. I hope like most people that I will always be able to find work, but I think that the field is going to be fairly stable for a long time. However, I’m sure there will be no shortage of headlines that have similar titles — “Is your job in jeopardy?” I also think that the article contents will usually say that it’s not.  I do think it’s a good idea to keep alert to changes in the industry because no career or company is invulnerable.

Work Cited:

https://www.forbes.com/sites/forbestechcouncil/2018/12/17/ai-in-software-testing-will-a-bot-steal-your-spot/#996553136710

From the blog Sam Bryan by and used with permission of the author. All other rights reserved by the author.

AngularJS is an open source web application framework. It was originally developed in 2009 by Misko Hevery and Adam Abrons. It is now maintained by Google. Its latest version is 1.2.21. AngularJS is a structural framework for dynamic web applications. It lets you use HTML as your template language and lets you extend HTML’s syntax to express your application components clearly and succinctly. Its data binding and dependency injection eliminate much of the code you currently have to write. And it all happens within the browser, making it an ideal partner with any server technology.

GENERAL FEATURES:

• AngularJS is an efficient framework that can create Rich Internet Applications (RIA).
• AngularJS provides developers an option to write client-side applications using JavaScript in a clean Model View Controller (MVC) way.
• Applications written in AngularJS are cross-browser compliant. AngularJS automatically handles JavaScript code suitable for each browser.
• AngularJS is open source, completely free, and used by thousands of developers around the world. It is licensed under the Apache license version 2.0.

Overall, AngularJS is a framework to build large scale, high-performance, and easy to maintain web applications.

CODE FEATURES:

Data Binding – It is the automatic synchronization of data between model and view components.

Scope – These are objects that refer to the model. They act as a glue between controller and view.

Controller – These are JavaScript functions bound to a particular scope.

Services – AngularJS comes with several built-in services such as $http to make an XML Http Requests. These are singleton objects which are instantiated only once in app.

Filters – These select a subset of items from an array and returns a new array.

Directives – Directives are markers on DOM elements such as elements, attributes, CSS, and more. These can be used to create custom HTML tags that serve as new, custom widgets. AngularJS built-in directives such as ngBind, ngModel, etc.

Templates – These are the rendered view with information from the controller and model. These can be a single file (such as index.html) r multiple views in one page using partials.

Routing – It is concept of switching views.

Deep Linking – deep linking allows to encode the state of application in the URL so that it can be bookmarked. The application can then be restored from the URL to the same state.

Dependency Injection – AngularJS has a built-in dependency injection subsystem that helps the developer to create, understand, and test the applications easily.

ADVANTAGES OF ANGULARJS:

• It provides the capability to create Single Page Application in a very clean and maintainable way.
• It provides data binding capability to HTML. Thus, it gives user a rich and responsive experience.
• AngularJS code is unit testable.
• AngularJS uses dependency injection and make use of separation of concerns.
• AngularJS provides reusable components.
• With AngularJS, the developers can achieve more functionality with short code.
• In AngularJS, views are pure html pages, and controllers written in JavaScript do the business processing.

DISADVANATAGES OF ANGULARJS:

Not Secure – Being JavaScript only framework, application written in AngularJS are not safe. Server-side authentication and authorization is must to keep an application secure.

Not degradable – If the user of your application disables JavaScript, then nothing would be visible, except the basic page.

 

References:

https://angularjs.org/

https://en.wikipedia.org/wiki/AngularJS

https://www.w3schools.com/angular/angular_intro.asp

From the blog CS@Worcester – Gloris's Blog by Gloris Pina and used with permission of the author. All other rights reserved by the author.

Hello dear reader. This is my last blog for my Software Construction and Design and as a very important part of development I choose to talk in this blog post for REST API.

REST API stands for Representational State Transferee and provides a lighter weight compared to SOAP. Instead of using XML to make a request, REST relies on a simple URL in many cases. In some situations, additional information needs to be provided. Most Web services using REST rely exclusively on obtaining the needed information using the URL approach. REST can use four different HTTP verbs (GET, POST, PUT, and DELETE) to perform tasks.
REST-based Web services output the data in Command Separated Value (CSV), JavaScript Object Notation (JSON) and Really Simple Syndication (RSS). The point is that you can keep the output you need in a form that’s easy to understand and use within the language you are using for your application. The information you receive when using REST is a JSON formatted document containing the information you asked for. You can use your browser to interact with the Web service, which makes it a lot easier to create the right URL and verify the output you need to parse with your application.
In most of the part REST is easier and more flexible to use. To use REST you do not need to purchase any tools, Postman or Insomnia can be downloaded for free. REST though, is efficient as it uses the small message formats and it has a fast process.
There are some very strong reasons that you should be using REST. First, REST is the most popular choice of programmers to build APIs.  Also REST API is great on making the data available as a resource as opposed to service.
To create a REST API, the following six architectural constraints are needed: 1. Uniform interface, which means that the same resource should not have more than one URL; 2. Client-server separating, which means that the client and the server should act independently. 3. Statelessness, which means that there should never be any server-side sessions; 4. Cacheable resources, means that the server responses should contain information even though the data sent might or not be cacheable; 5.Layered system, which means there might be different layers of servers between the client and the server that returns the purpose; 6. Code on demands, which means that the response can contain code that the user can execute.

If I also refer to the previous blog about SOAP API I would say that there are clearly good reasons why REST API is a better choice to use when requesting/ expecting data and when you want to build your own program. However the decision is yours. I hope I have helped your CS journey. Till next time…

https://en.wikipedia.org/wiki/Representational_state_transfer

From the blog CS@Worcester – Danja's Blog by danja9 and used with permission of the author. All other rights reserved by the author.

As I take my final step towards my journey in software C.D.A. this blog would be the last one regarding my journey with learning and researching topic related to my class Software Construction Design and Architecture. For this blog I will be talking about the blog “API management with Kong” by Alexander Melnyk. This blog is about the importance of API management and why does it matter. It also focuses on the Kong Architecture.

In the blog it explain why API management matter. The idea of API management is that it plays an important role when it comes to integration. Which can be done “by providing clear boundaries and abstractions between systems”. The blog also explains a few “ways to tackle the technical complexity and how Kong API gateway can help deal with it”. You may be wondering what is Kong it is an open source API gateway to manage RESTful APIs.” However the blog gives a better description of what and how it is use for. There are five components of Kong architecture:

1. nginx – “The core low-level component” also the most popular used web server.
2. OpenResty – “a web platform that glues nginx core, LuaJIT, Lua libraries and third-party nginx modules to provide a web server for scalable web applications and web services.”
3. Datastore – is a component that “uses Apache Cassandra or PostgreSQL to handle the storage of the configuration data, consumers, and plugins of all APIs.”
4. plugins – “are Lua modules that are executed during a request/response life-cycle. They enrich the API gateway with functionalities for different use cases.”
5. RESTful admin API – It is used to manage the API and provide an important tool to automate developers workflows.

The blog goes on and covers the Kong API gateway in action which “will show you how to create a minimal infrastructure for Kong API gateway. Then I will add an API and a security plugin to restrict the access to a specific user.” and then covers the consumers and plugins. If you have found this topic interesting or if your curiously left with question click on the title link above and read the blog the blogger does a much better job at explaining and getting the message across then I do.

Personally I really enjoyed reading the blog because it helped me realize that the Kong Architecture is in fact very useful and important. I also found the blog to be well written full of useful and important information that will benefit me as a software developer.

Thank you for your time. This has been YessyMer in the World Of Computer Science, until next time.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

From the blog cs@Worcester – YessyMer In the world of Computer Science by yesmercedes and used with permission of the author. All other rights reserved by the author.

For this week’s blog, I am choosing test-driven development what is and what it is not by Andrea Koutifaris.

Test-driven development(TDD) is a software development process that relies on the repetition of a very short development cycle. First, developers write a failing test case then produces the minimum amount of code to pass that test and finally refactors it to acceptable standards.

There are three processes that are often described using TDD: Red/Green/Refactor cycle.

Red phase

In the red phase, you write a test that uses a piece of code as if it were already implemented. Without implementation and not thinking about production code, this phase is where you concentrate on writing a clean interface for future users and where you design how your code will be used by clients. The Red phase is the most important phase and it is the rule that makes TDD different from regular testing. You write tests so that you can write production code and not test your code.

Green Phase

For developers, the green phase is probably the easiest part of a TDD. This is the part where you write code but not the whole implementation, just enough for the test to pass. Make all the alarming red on the test report becomes green. In this phase, you do not need to worry about violating best practices since we will do that in the Refactor phase. This phase exists to make your task simpler and less prone to error.

Refactor Phase

In this phase, you are allowed to change the code while keeping the tests green. But there is something mandatory, that you have to remove code duplication. In this phase, you can worry about algorithms and such to make the program better. This is the phase where you can show off your skills to your users.

 

I really liked reading this blog and I kind of liked the idea of Test-Driven Development. I think doing it this way creates more code coverage and thus fewer bugs later on. This kind of development is a bit unique to me since I have only done behavior-driven development so far. Test-driven development changed my mind in a way. I think that doing test-driven development is more beneficial, kind of like reverse engineering, we start from something that we know is gonna work then proceed from there.

 

From the blog CS@Worcester – Computer Science by csrenz and used with permission of the author. All other rights reserved by the author.

Source: https://www.guru99.com/mutation-testing.html

This week’s reading is on mutation testing. It is stated to be a technique that changes certain statements in the source code to see if the test cases are able to find the errors. The overarching objective of mutation testing is accessing the quality or robustness of the test cases. These mutations are generally placed in several categories, operand replacement, expression modification, and statement modification. For operand replacement, an example would be simply replacing a variable in an if-statement with a constant. For expression modification, an example would be to replace a less than or equal to operator to a greater than or equal to operator. Lastly, for statement modification, an example would be simplify deleting lines of code, adding code, or modifying data types in the program. This type of testing allows the testers to uncover errors that would have remained undetected. By comprehensively testing the tests, it will provide a large amount of code coverage of the source code. It is a very useful white-box testing technique.

I found that the article provides great depth on mutation testing, steps on how the technique works, advantages, disadvantages, and provide examples. This serves as a great refresher to the activity done in class. Before that, I would have never thought about a software technique that provides such coverage to the tests already created. I can agree with the article that it is powerful tool that brings adequate amount of error detection. It will improve code quality and early bug detection will save costs later on in development if they are caught early using mutation testing. What I found most interesting about mutation testing in general is the mutation score. It is defined as the percentage of killed mutants with the total number of mutants. By observing the percentage of killed mutants, we can see if the test cases are effective against the mutations. Unlike other white-box testing techniques, it is a very unique way of effectively testing tests for their techniques. This is similar to the black-box testing technique fuzzing, where it creatively creates unexpected creative inputs for software to uncover bugs that would have otherwise been missed. In conclusion, this exhaustive technique is very useful for comprehensively testing a program and is very effective.

From the blog CS@Worcester – Progression through Computer Science and Beyond… by Johnny To and used with permission of the author. All other rights reserved by the author.

When we think of AI, we usually think of robots doing certain actions that can replace basic human actions. Sometimes these actions aren’t basic at all. Development timelines have also changed drastically. This Forbes article talks about how AI can potentially take over testing phases due to the shorter time-frames for gold standard releases. With more and more companies releasing software, there will naturally be more competition. Not only is the competition driving this push for AI software testing, but also efficiency. Another thing that drives a push for AI software testing is cost structures. A lot of companies are based on certain cost structures which can heavily impact the quality of a product. With the amount of testing needed for a product to be in working conditions, you may need a lot of people per team to test software. Software testing AI seeks out to have this issue resolved or at least assisted. But, the main reason that AI in software testing is mainly due to narrow constraints of time. Since deadlines are always being set shorter and shorter while standards are being set higher and higher, it seems like the logical solution is to find the easiest and most effective way to combat these restraints

This is an interesting topic because it’s something that you wouldn’t really think would make much sense. If you development an AI to test software, then this could still potentially leave the software vulnerable to bugs. This is due to the fact that there are added variables and “middlemen” added into the equation if you have automated testing. Now, not to say that AI testing is useless, as it is probably extremely efficient at testing a lot of smaller things at once, however it seems like it could be added overhead. New roles would have to be assigned for teams just to test the software for the AI that is testing the software. In concept, AI testing seems like a great idea. However, there are bound to be bugs and whether or not it is worth the risk and cost to implement AI software testing is ultimately up to the companies do it. It is a very unique topic and will be interesting to see just how companies will implement this in the future.

Article: https://www.forbes.com/sites/forbestechcouncil/2018/12/17/ai-in-software-testing-will-a-bot-steal-your-spot/#63c50ce36710

From the blog CS@Worcester – Amir Adelinia's Computer Science Blog by aadelinia1 and used with permission of the author. All other rights reserved by the author.

In recent times, it seems as though a few companies are letting major security flaws slip through their developer tools. A few days ago, Facebook had a massive 8+ million user exposure due to a flaw in their Photos API. This bug allowed photos of users using certain apps with this API to have their data leaked and pulled without their knowledge. Facebook didn’t realize this until 12 days after this had occurred. Now, Google is in a similar boat. A few days ago, on Monday, Google revealed that it’s Google Plus social media network site (that was in the process of shutting down) also had an API bug that, again, exposed the information of users. This time on a much larger scale. Google’s API exposure hit over 51 million users. Interestingly enough, this happened just two months after they had discovered another bug that exposed data of 500,000 users. This was the initial reason for Google Plus to ultimately shut down. Although Google reported that there was no evidence of this data being “misused”, this information is still out there and the attention will surely seek the eyes of many who will misuse it.

So why is locking down an API so important? An API is a predefined set of tools that are used by developers to perform multiple actions in program. A lot of these are protocols that either pull certain information or perform various tasks. The API is the middle ground of how software can talk to each other. When there is an API bug, this can lead to information that is not suppose to be able to be pulled, get exposed to fields that should not be able to. This was the case with Facebook’s Photo API, and now the case with Google’s Google Plus media API. What we can learn from this is, whenever you are modifying or testing with API’s, always make sure that boundary tests are in place to make sure that certain data can not be pulled by any alternative means. Most of the time, only authorized developers are only permitted access to certain API’s, nullifying any outside attacks. However, if an API does not have the correct stops and security in place, user data is at a massive risk as shown by these two examples of mass user data exposure.

 

Article: https://www.softwaretestingnews.co.uk/17470-2-google-plus-closure-api-bug/

From the blog CS@Worcester – Amir Adelinia's Computer Science Blog by aadelinia1 and used with permission of the author. All other rights reserved by the author.

And the biggest question if the software testing is manual testing vs automatic testing? Why do we need automated testing?

@All Welcome to my last blog post for my Software Test class. As a last blog post for this class I wanted to talk about the Automated Testing.

From the name we can tell that Automated Testing is automated. Automated testing is done through an automated tool, which is needed in exploratory tests and in maintaining test scripts while increasing overall test coverage. Automated Testing is usually used for large projects that require testing the same area lots of times.
Automated Testing has its own implementing strategy which consist in the shape of a pyramid. This strategy calls for automating testing at three different levels. The biggest percentage of this test automation pyramid goes to unit testing. The is followed from API testing and UI testing.

Software tests have to repeated often during development cycles to ensure quality. Every time the source code is modified, software test should be repeated. From my experience at my work, we recently automated the testing and deployment process for one of our systems. For every deployment, we had to test every connected system. One of the benefits of Automated Testing is that is much faster than the manual testing and it also can reduce the time to run repetitive tests all the time. In my opinion time savings equals cost savings. Another benefit of Automated Testing is it increases the test coverage.  It can easily execute thousands of different complex test cases during every test run, providing coverage that is almost impossible with manual testing.

https://www.qasymphony.com/blog/test-automation-automated-testing/

Kyle makes a good point in explaining the differences between the test automation and automated testing as its important to know the difference.

From the blog CS@Worcester – Danja's Blog by danja9 and used with permission of the author. All other rights reserved by the author.