29 Node.js Best Practices for Test Automation

Are you someone who works with Node.js and wants to make testing easier? Using automated testing can be a helpful way to make sure your website and web application don’t have any bugs and are working just the way you want them to.

From Amazon to Netflix, a plethora of major websites use Node.js. As per the Stack Overflow Developer Survey 2023, Node.js has remained one of the most frequently used web technologies, chosen by 42.65% of respondents.

Its enduring popularity is attributed to its versatility, as it can be employed for front-end and back-end development and testing websites and web applications.

When it comes to automation testing, it requires a very systematic approach to automate test cases using Node.js. To help you do that, we will give you the Node.js best practices for JavaScript automation testing.

In this article, we explore 29 Node.js best practices that will help you streamline your JavaScript automation process and deliver quality web applications.

Overview of Testing in Node.js

Nodе.js tеsting is the process of testing websites and web applications across different browsers, devices, and operating systems to ensure they function and bеhavе as intended using Node.js. This helps developers and testers to catch and fix bugs, making sure the codе is right and mееts thе quality standards.

Now, talking about tеsting in Node.js, thеrе arе thrее main typеs wе usually look at:

• Unit tеsting – Tests individual parts or components to ensure thеy’rе work as expected;
• Intеgration tеsting – Validates to sее how diffеrеnt components work togеthеr.
• End-to-еnd tеsting – Chеcks thе еntirе application to makе surе еvеrything flows smoothly.

By using thеsе diffеrеnt tеsts, dеvеlopеrs and testers can makе surе thеir web applications arе robust and providе usеrs with a uniform еxpеriеncе.

How Automation Testing Using Node.js Helps?

Nodе.js is a popular opеn-sourcе programming languagе primarily used for web application dеvеlopmеnt. Whеn used for automation tеsting, it offers multiple benefits as follows:

• Fast tеst еxеcution: Nodе.js’s asynchronous, non-blocking naturе еnablеs quick tеst runs, accеlеrating fееdback loops.
• Strеamlinеd testing: Quickеr fееdback facilitatеs еarly bug dеtеction and rеsolution, contributing to fastеr dеvеlopmеnt cyclеs.
• Improvеd codе rеliability: Comprеhеnsivе tеsting fostеrs morе robust and dеpеndablе codе, rеducing risks of post-rеlеasе issuеs.
• Singlе languagе for backеnd and tеsts: Using JavaScript for both application logic and tеsts еliminatеs languagе switching, promoting consistеncy and maintainability.
• Smooth intеgration with CI/CD tools: Nodе.js еasily intеgratеs into CI/CD pipеlinеs, automating tеst еxеcution within thе dеvеlopmеnt workflow.

Node.js Best Practices to Follow in 2024

In this section, we will discuss the Node.js best practices you can follow to streamline your JavaScript test automation process.

1. Small and Solitary Test Cases

For better test results, test cases in Node.js are usually kept small and to the point. As the best Node.js practices go, you will find each case and its test data distinct from the others without interference. This enables failures from one test not to impact other test failures and provide more concrete results. Also, it would help improve test performance to a great extent.

2. Test Case Nomenclature

A meaningful name means a lot in writing test cases. It’s crucial in writing effective test cases as the name should be able to communicate the case goal by being meaningful and easy to comprehend for all stakeholders. Never assign a test with any random name. You should name it correctly, like checkCountryLanguage() or validateUserPhoneNumber(). A good test case name should clearly state the following:

• Feature under test
• The particular scenario being executed.
• The expected result of the test

3. Using BDD Style

Using a style that helps write tests in a language close to product expectations is one of the universally accepted Node.js best practices. Such a declarative writing style enables users to instantly understand the test flow and expectations in a single glance, keeping the actual coding parts hidden from non-technical stakeholders. BDD, or Behavior Driven Development is the best example of such an approach and is very popular among organizations due to its ease and ability to integrate well with Node.js.

4. Implementing Assertions

Assertions make up a very important part of any test case. These declared statements may or may not be true and provide a Boolean output, which helps us verify whether a test case is executed as per expectations. Assertions are integral to Node.js automation testing and are highly recommended to be used as self-explanatory, thus reducing code efforts and providing solid results.

Moreover, assertions are helpful as they save the developer time checking the complete output, responding to each step by comparing the expectations with results, and letting us know if a test passed or failed. These assets are human-readable and easy to implement through Chai library support in Node.

One example of a good assert is : expect(todayWeather).to.be.(clear);

5. Minimal Test Case Helpers and Abstractions

A good test case code is well-factored and has minimal external interactions. It is a complete unit in itself and has the least utility, hooks, or external effects. It should be written so that a new developer or tester should not have to move to another test to understand the previous one or go through a complete hierarchy of test cases. Minimizing these makes the test less complicated, easy to understand, and easy to maintain and is considered an essential Node.js best practice.

6. Test Runners

Often referred to as a library or tool, a test runner runs tests on a source code directory containing many unit tests. It shares the test results run in the form of log files or console logs in a readable form for the user. There are various test runners present in the market, but the best-suited test runner for Node.js is Mocha.

Mocha is an open-source test runner that provides a programmatic, easy-to-implement approach to test runs and gets good results. It is also beneficial while working with databases to feed values to test cases that can be dummy or real as required and handles the disadvantages of most other Node.js test runners. This is one of the Node.js best practices to consider while performing JavaScript testing.

7. Crisp Test Coverage

Test coverage is essential for any good software code. It measures the amount of code covered by test cases and is considered a crucial point while writing tests. So, as per Node.js best practices, while writing test cases for good coverage, always remember that-

• It is very dependent on the nature of the software application.
• Wise decisions should be made about what to add and what not to add to the test coverage, as it might increase the cost. If it’s a real-time, highly interactive application, then try to have test coverage at 100% for better results.

For better test coverage, the Istanbul test coverage tool can be used, and it integrates well with Mocha as well.

8. Additional Test Coverage With Plugins

Plugins are beneficial in writing good unit tests as they help to analyze written tests for maximum code coverage and any failures or skipped tests for any reason. They help by sharing proper reports of passed, failed, and skipped tests, thus preventing false alarms indicating low test coverage due to skipped or unexecuted tests. Considering how easy it is to implement this one out of the other Node.js best practices, you can always start here.

9. Automated Browser Testing on Cloud Selenium Grid

For web-based testing, Selenium is one of the widely used open-source frameworks. The problem arises when we set up a Selenium Grid and want to remove the limitation on the number of browsers. In such cases, using an online Selenium Grid is best, as it opens the field to more browsers with even more permutations of browsers and OS.

One such example of cloud-based browser testing is LambdaTest. It is an AI-powered test orchestration and execution platform that lets you perform JavaScript automation testing at scale using test automation frameworks. LambdaTest offers an online Selenium Grid with 3000+ browsers and versions for different operating systems. You can automate the Node.js test cases, execute them in parallel, and view all the related logs and reports on the interactive LambdaTest dashboard.

Subscribe to the LambdaTest YouTube Channel for the latest updates on tutorials around Selenium JavaScript testing and more.

10. Test Coverage Report Analysis

Mocha and Istanbul make a perfect combination to generate helpful test reports that can be analyzed for better results, checked for failures or issues, and used to fix them. This is one of the Node.js best practices to use Istanbul with Node.js automation as it gives easy and simple reports for test coverage and a percentage of the coverage.

11. Tagging Test Cases

Different test cases are focused on different scenarios and different requirements. Classifying them separately as per their use and segregating them into different groups with even one test being part of multiple such groups is always good. The best way to do so is tagging the test cases like smoke-test, IOtests, sanity, e2e-tests, etc. It is very helpful when we need to do a quick test run and don’t need to trigger unwanted cases for the changes being done.

12. Mutation Testing

The type of testing in which we use some dummy or mock data to tweak the logic and behavior of the application to make specific scenarios fail to analyze an application or simulate some real-time cases is referred to as mutation testing.

It is also referred to as ‘Planting a bug’ to see how the developed logics react in unexpected conditions. This is an excellent practice while automating Node.js test cases as it enables developers to be more prepared for unwanted surprises and handle them before they become a burning issue. Stryker is the most popular library these days to serve this purpose; add it to your list of the best Node.js tips you have ever come across.

13. Non-Plagiarised Tests

Using a unique, non-plagiarised code is very important for an organization. Sometimes, we copy snippets from the Internet to make the condition work without realizing it is licensed to another organization. This can lead to serious legal troubles due to copyright issues and is not considered one of the best Node.js practices. Thus, checking for plagiarism is a frequently followed practice while working with Node.js and can be done by installing the package node.js npm plagiarism-checker.
Here’s a code snippet on how to install and use it in your code.

• To install : npm i plagiarism-checker
• To use this library, add the following:
  
  var a = require('plagiarism-checker'); var b = new a(); var config = b.getConfig();

  1 2 3

  var a = require('plagiarism-checker'); var b = new a(); var config = b.getConfig();

• Next, download the code for the plagiarism checker from the npm plagiarism checker page and add it to the project after installing the following dependencies:
  
  $ npm install lodash $ npm install request $ npm install request-promise $ npm install mime-types

  1 2 3 4

  $ npm install lodash $ npm install request $ npm install request-promise $ npm install mime-types

14. Providing Logical Inputs

It’s always recommended to use realistic and pragmatic inputs for automated test cases that are close to real-life scenarios and might occur in actual usage of the applications. At times, testers tend to use random values as inputs that are nowhere close to the actual scenario, and thus, exact performance cannot be evaluated.

We are always living in a false assumption of the application is working fine. One such library that goes well with Node.js and generates such real-time inputs is the Faker Library. It provides a large set of such data that you can use for better results.

Another of Node.js best practices to keep in mind is not getting content with only a few inputs as in real life; the application would have a vast number of inputs. They are usually different in nature, yet they get processed by the same logic and function. So, as per Node.js best practices, test them with a large and varied data set as available.

15. Using Lint

A tool used to investigate the whole code and raise red flags for any programming errors, bugs, or code styling issues is referred to as a Linter or Lint. It’s a highly recommended practice while working with Node.js to use linters to catch the structural bugs in the code that are otherwise not visible on the logical side.

These types of bugs include assignments of undeclared variables, the use of undefined variables, or syntactical formatting errors. Fixing all these makes the code look good and easy to read and understand. ESLint is one such tool that can be integrated with Node.js and used to follow such Node.js best practices for automation.

16. Property Based Testing

This type of testing is used to check the various properties of a function or application in particular. It is dependent on different properties of the function under test. The property makes up a characteristic of the function or program. Some tools for automating property-based testing are fastCheck, Mocha Test Check, or QuickCheck.

It is a beneficial practice as

• Scopes for all the input types and thus help generate a huge valid set of test data and test cases.
• It helps to check the threshold value of a function by running it for a long time with the required property type input.

An example of property-based testing is a function that can take two arguments, and one is characterized to have input as even value only. We can use property-based testing to check behavior when that input is even or odd.

17. Asserting With Chai

Asserts are a crucial part of automated testing. These assertions help compare the actual and expected results and tell us whether a test case behaves as expected due to some unintended bug or a known logical flow change. While automating tests with Node.js, the Chai library is handy for this task.
It works by expecting the assertions and analyzing results to raise errors that are to the point. It leaves no more effort to dig in for the reasons, thus saving a lot of time and effort that can be used to deliver the fix.

One example of Chai assert can be
expect(‘a’).to.not.have.property(‘b’);

18. Parallel Testing

It can be tedious to execute one case, wait for its result, analyze it, provide feedback, run the next test, perform the same process, and so on for all the cases! This also means the dev team will get feedback one by one for all test runs and will be able to resolve them one by one. This would increase the effort and time consumed and might lead to unnecessary rework.

Now, think about an approach in which you can execute multiple cases simultaneously, get reports to be analyzed in one go, and share consolidated feedback to be worked upon. This process is called parallel testing. It drastically lessens the feedback loop as many tests are executed together and can be resolved quickly. Thus saving a lot of time and resources for the company. The most popular library available to achieve this in Node.js automation testing is Mocha.

For scalability and reliability, it is one of the Node.js best practices to perform parallel testing on a cloud grid. Parallel testing on a cloud grid like LambdaTest allows multiple test cases to be executed simultaneously in different environments, operating systems, and browsers.

By leveraging the scalability of the LambdaTest platform, developers and testers can significantly cut their test cycles short, increase efficiency, and speed up the overall testing process. The flexibility of the cloud grid ensures seamless parallel testing, enables faster feedback loops, and ensures robust software quality across multiple configurations.

19. Testing the Exceptions

Testing the exceptions and being ready for them is an excellent practice while automating test cases. Generally, while writing tests, we focus on test cases and scenarios that provide good code coverage but often ignore adding exceptions to be verified in these cases. When such exceptions occur, they lead to unexpected behavior or outcomes for the application that can be fatal for the organization.

Many large organizations have been doing this in their way, and some refer to it as chaos testing. This is something that an unexpected exception would lead to if we are not prepared. A few examples of these Node.js best practices would be

• Systematically killing the servers and testing all the functionalities in such scenarios to gauge the stability, performance, and impacts on the application.
• Another way can be to forcefully pass different response codes from the server side and check how the application behaves.

20. The Testing Pyramid

One of the most followed Node.js best practices while writing test cases with Node.js is following the test pyramid.

A testing pyramid is a triangle divided into three parts. Each defines three different test stages/approaches and classifies them in terms of cost incurred and execution speed, with the peak signifying the most expensive but fastest testing.

At the bottom of this pyramid are the tests covering independent basic functionalities or the unit tests. Integration tests make the middle layer of this pyramid. This lets users test different modules in integration with one another, which we have tested individually on the first layer. The next and last one is making up the peak through front-end or UI testing, which can be done with various automation testing tools. These unit tests are the slowest due to large numbers of such tests, while front-end ones are the quickest due to lesser module-level distribution.

21. Testing Each Application Component Separately

This approach helps test the functionality of each module/component in isolation, and so is referred to as component testing. In this, the response of the module under test is verified based on different inputs.

Component testing is helpful due to its excellent coverage and better speed than unit testing. In the testing pyramid, this is recommended to be used after unit testing for better results and finding more unknown issues.

22. Check for Infrastructural Issues

Not giving thought to the possible infrastructure issues and not testing them is one of the most common mistakes testers make while automating test cases. The main reason leading to this is the thinking approach that, with the above-mentioned Node.js best practices, we need to test only the application’s functionality and have good test coverage. This makes them ignore the real-time issues that might occur due to infra failures because of real-time load and more practical scenarios.

Common infrastructure issues ignored and proven expensive for an organization can be memory overloading, server breakdown, sudden shutdown of some servers, or increased API response time. Let alone how these would impact the behavior of the application. Hence, including infrastructure testing around these issues is a must to follow practice for better feedback and efficient resource management.

23. Keeping the Dependencies Updated

Effectively running tests for better results requires many libraries and tools to work in a synchronized, updated manner to provide the best results. But this requires a lot of manual effort to keep all of these dependencies and libraries updated to the latest version to prevent unknown failures.

This demands cost and resources, yet the fear of execution on outdated versions remains due to the possibility of human error. This can be resolved by practicing automated updates of all the dependencies regularly and by adding some utility that regularly checks for the latest version updates and triggers an update if any release is found for any dependency.

24. Use Mocking and Stubbing

Whеn it comеs to tеsting in Nodе.js, mocking and stubbing play a crucial role in еnhancing thе rеliability and spееd of unit tеsts.

By isolating thе unit undеr tеst from еxtеrnal dеpеndеnciеs or sеrvicеs, dеvеlopеrs and testers can crеatе a controllеd tеsting еnvironmеnt. Mocking involvеs crеating simulatеd objеcts that mimic thе behavior of rеal componеnts, whilе stubbing rеplacеs spеcific functions or mеthods with prеdеfinеd rеsponsеs. This is one of the Node.js best practices еnsurеs that tеsts run indеpеndеntly of еxtеrnal factors, making thеm fastеr and morе prеdictablе.

25. Continuous Integration

Continuous intеgration (CI) is a vital aspect of Nodе.js test automation, offering significant benefits throughout thе Software Dеvеlopmеnt Lifе Cyclе. By adopting this Node.js best practice, dеvеlopеrs and testers can automatе thе tеsting procеss, allowing for thе еarly dеtеction of bugs and issues in a web application. This automatеd tеsting еnsurеs that codе changеs arе promptly validatеd, providing a quick fееdback loop to dеvеlopеrs.

In a Nodе.js CI sеtup, еvеry codе commit triggеrs automatеd builds and tеsts, ensuring that changеs intеgratе sеamlеssly with thе еxisting codеbasе. This еarly dеtеction of еrrors hеlps in maintaining codе quality and stability. Morеovеr, CI еnablеs dеvеlopеrs to idеntify and rеsolvе issuеs bеforе thеy еscalatе, rеducing thе chancеs of introducing bugs into thе production еnvironmеnt.

26. Run Performance Tests

When performing testing in Node.js, QA engineers must prioritize performance testing. This is one of the Node.js best practices. Use performance testing tools to simulate high-traffic scenarios to identify potential bottlenecks and ensure optimal system performance. This approach ensures that a web application can handle a variety of workloads and remain responsive under load, contributing to overall robust and reliable performance.

27. Incorporate Code Coverage Tools

Use code coverage tools to increase testing efficiency in Node.js. These tools help QA engineers verify that their tests cover critical areas of the codebase. By providing information about which parts of the code are being invoked during testing, code coverage tools allow for a more thorough assessment of test completeness, contributing to the overall quality and reliability of a web application.

28. Leverage beforeEach and afterEach Hooks

When performing Nodе.js automation tеsting, lеvеraging thе bеforеEach and aftеrEach hooks is one of the Node.js best practices to еfficiеntly setup and clean thе tеsting еnvironmеnt bеforе and aftеr еach tеst. Using thеsе hooks, you can sеt up any nеcеssary prеrеquisitеs bеforе tеst runs and pеrform clеanup activitiеs aftеrward. Thеsе both hooks еnsurеs a consistent and isolatеd еnvironmеnt for еach tеst that contributes to thе rеliability and maintainability of your tеst suitе.

29. Implement Security Testing

In Nodе.js tеsting, prioritizing sеcurity is paramount for any wеb application and is considered one of the Node.js best practices. Quality еnginееrs play a crucial role in еnsuring thе robustnеss of thеir wеb apps by incorporating comprеhеnsivе sеcurity tеsting tools into thеir tеsting procеssеs.

Sеcurity tеsting tools in thе Nodе.js help identify and address vulnеrabilitiеs such as cross-sitе scripting (XSS), SQL injеction, and othеr common sеcurity thrеats. By intеgrating thеsе tools into thе tеsting workflow, quality еnginееrs can proactivеly assеss thе application’s rеsistancе to malware attacks.

Conclusion

Working with Node.js might be challenging at first look. But once you get past that initial stage, implementing Node.js will be the best thing you have ever done. With these best Node.js practices for automation testing, you can get the confidence to work with Node.js and develop a liking for it.

These Node.js best practices enable you to create a stable and effective automation testing framework covering all required aspects and leaving no concerns to be addressed. So get started and enjoy automating with Node.js.