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JavaScript, NodeJS & React Online Test

About the test:

The JavaScript, NodeJS & React Test uses scenario-based MCQs to evaluate candidates on their proficiency in JavaScript programming language, NodeJS runtime environment, and React library for front-end development. The test assesses candidates' understanding of topics such as component-based architecture, state management, React Hooks, server-side rendering, and virtual DOM. Candidates are evaluated on their ability to use JavaScript, NodeJS, and React to develop responsive and scalable web applications, as well as their proficiency in writing optimized and secure code.

Covered skills:

  • JavaScript Basics
  • JS OOPs
  • Asynchronous Node.js and promises
  • Request Response Lifecycle
  • React Component Lifecycle
  • JavaScript Programming
  • JS ES6
  • Handling APIs
  • Node.js Module System
  • Building components with JSX
  • React Hooks and functional components

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9 reasons why
9 reasons why

Adaface JavaScript, NodeJS & React Test is the most accurate way to shortlist JavaScript Developers



Reason #1

Tests for on-the-job skills

The JavaScript, NodeJS & React Online Test helps recruiters and hiring managers identify qualified candidates from a pool of resumes, and helps in taking objective hiring decisions. It reduces the administrative overhead of interviewing too many candidates and saves time by filtering out unqualified candidates at the first step of the hiring process.

The test screens for the following skills that hiring managers look for in candidates:

  • Able to efficiently handle exceptions and errors
  • Strong understanding of JavaScript syntax and functions
  • Proficient in ES6 features such as arrow functions and template literals
  • Knowledge of Object-Oriented Programming principles in JavaScript
  • Experience in handling APIs and making AJAX requests
  • Understanding of asynchronous programming concepts in Node.js using Promises
  • Familiarity with Node.js Module System and how to organize code into modules
  • Understanding of the request-response lifecycle in Node.js
  • Ability to build components using JSX in React
  • Knowledge of React Component Lifecycle and how to manage component state
  • Familiarity with React Hooks and functional components
  • Proficiency in JavaScript programming
Reason #2

No trick questions

no trick questions

Traditional assessment tools use trick questions and puzzles for the screening, which creates a lot of frustration among candidates about having to go through irrelevant screening assessments.

View sample questions

The main reason we started Adaface is that traditional pre-employment assessment platforms are not a fair way for companies to evaluate candidates. At Adaface, our mission is to help companies find great candidates by assessing on-the-job skills required for a role.

Why we started Adaface
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Reason #3

Non-googleable questions

We have a very high focus on the quality of questions that test for on-the-job skills. Every question is non-googleable and we have a very high bar for the level of subject matter experts we onboard to create these questions. We have crawlers to check if any of the questions are leaked online. If/ when a question gets leaked, we get an alert. We change the question for you & let you know.

How we design questions

These are just a small sample from our library of 10,000+ questions. The actual questions on this JavaScript, NodeJS & React Test will be non-googleable.

🧐 Question

Medium

Async Await Promises
Promises
Async-Await
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What will the following code output?
 image
A: 24 after 5 seconds and after another 5 seconds, another 24
B: 24 followed by another 24 immediately
C: 24 immediately and another 24 after 5 seconds
D: After 5 seconds, 24 and 24
E: Undefined
F: NaN
G: None of these

Medium

Bitcoin prices
Axios
Promises
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Review the following JavaScript code and pick the correct options: 
 image
Assume that the API returns a successful 200 response code and a JSON object as the response body. What would the value of ‘a’ be after the code is executed?

Medium

My Module
Scope
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What will the output of the following JavaScript code be?
 image
 image

Medium

Promise Resolve
Promises
Async-Await
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What does the following code output? 
 image

Easy

Throw, Try, Async
Promises
Async-Await
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What does the following JS code output?
 image

Medium

I/O cycle and main module
Event Loop
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Review the following NodeJS code:
 image
Pick the correct statements:

A: X will be logged after Y always
B: Y will be logged after X always
C: The order of executing timeout and immediate callbacks is non-deterministic and is bound by the performance of the process
D: In this case, the function calls are scheduled in the main module and not in the I/O cycle
E: In this case, the function calls are scheduled in the I/O cycle so setImmediate is always executed before any timers scheduled in the I/O phase, independently of how many timers are left

Easy

Res methods
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If none of the methods (res.download, res.end, res.json, res.jsonp, res.redirect, res.render, res.send, res.sendFile, res.sendStatus) are called from a route handler to terminate request response cycle, what happens to the the client request?
A) Will be left hanging indefinitely

B) Will get an internal server error - 500 

C) Will get a service unavailable error - 503

D) Will be left hanging for a while and then request timeout error - 408

Medium

Phases and Timers
Event Loop
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Review the following NodeJS code:
 image
Pick the correct statements:

A: Adaface will be logged after Lovelace.
B: Lovelace will be logged after Adaface.
C: Once the asyncOpThatTakes195ms completes reading the file, it starts executing the callback which takes 10 seconds. Only after this is finished, the event loop will execute the timers that are finished. So the timeout call back will actually be executed after 205 ms even though it is scheduled to be run after 200 ms
D: Once the asyncOpThatTakes195ms completes reading the file, it starts executing the callback. While executing the callback, the scheduled timer becomes ready to be executed. So the runtime executes the timer and then completes processing the callback.

Hard

Context re-renders
React Context API
Conditional Rendering
Component Lifecycle State
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Review the following React code:
 image
Pick the correct statements:

A: The code renders 10 INDIAN RUPEE
B: The code renders 10 SINGAPORE DOLLAR
C: The code does not render anything and throws an error since JavaScript objects are not valid as React children
D: When the currency portion is clicked, the parent component is re-rendered
E: When the currency portion is clicked, parent component will skip the re-render because shouldComponentUpdate returns false
F: Parent component can be converted to a functional component with memoization (useMemo or memo) to avoid the re-render

Medium

Hooks with Conditional Rendering
Hooks
Conditional Rendering
Event Handling
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Consider a React functional component that utilizes various hooks and conditional rendering. The component is designed to fetch and display a list of items from an API, with the ability to filter the list based on user input. Here's the pseudo-code structure:
 image
In this component, which of the following is a potential issue or inefficiency?
A: The component will re-render excessively due to the `setFilter` call.
B: The `useEffect` hook will run on every render, causing performance issues.
C: The `fetchItems` function may cause a memory leak if the component unmounts during the fetch.
D: The `useMemo` hook for `filteredItems` is unnecessary and can be removed without impact.
E: The component will fail to display items when the filter is cleared.
F: There are no significant issues; the component is implemented optimally.

Medium

Rhyme Reducer
Reducer functions
Immutable update patterns
Lazy initialization
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Which of the following React code snippets
- triggers the reducer ‘rhymeReducer’ to update the ‘song’ value to ‘Jack and Jill’
- renders the updated ‘song’ value
- does not produce any errors/warnings
 image
 image

Hard

State Handling with Custom Hooks
Custom Hooks
Context API
Event Handling
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Consider a React application where a custom hook `useComplexState` is defined to manage a complex state object. The application also uses the Context API to pass down the state and dispatch function. Below is the pseudo-code for the custom hook and a component using it:
 image
Given this setup, which of the following statements best describes the potential issue or challenge with `MyComponent`?
A: The component will not re-render when the global state changes.
B: The `fetchData` function will cause an infinite loop of re-renders.
C: The component will lose its state when the global state updates.
D: There will be a memory leak due to improper cleanup in `useEffect`.
E: The `dispatch` function from `useComplexState` will conflict with the global dispatch.
F: There is no issue; the component is implemented correctly.

Easy

Registration Queue
Logic
Queues
Solve
We want to register students for the next semester. All students have a receipt which shows the amount pending for the previous semester. A positive amount (or zero) represents that the student has paid extra fees, and a negative amount represents that they have pending fees to be paid. The students are in a queue for the registration. We want to arrange the students in a way such that the students who have a positive amount on the receipt get registered first as compared to the students who have a negative amount. We are given a queue in the form of an array containing the pending amount.
For example, if the initial queue is [20, 70, -40, 30, -10], then the final queue will be [20, 70, 30, -40, -10]. Note that the sequence of students should not be changed while arranging them unless required to meet the condition.
⚠️⚠️⚠️ Note:
- The first line of the input is the length of the array. The second line contains all the elements of the array.
- The input is already parsed into an array of "strings" and passed to a function. You will need to convert string to integer/number type inside the function.
- You need to "print" the final result (not return it) to pass the test cases.

For the example discussed above, the input will be:
5
20 70 -40 30 -10

Your code needs to print the following to the standard output:
20 70 30 -40 -10

Medium

Visitors Count
Strings
Logic
Solve
A manager hires a staff member to keep a record of the number of men, women, and children visiting the museum daily. The staff will note W if any women visit, M for men, and C for children. You need to write code that takes the string that represents the visits and prints the count of men, woman and children. The sequencing should be in decreasing order. 
Example:

Input:
WWMMWWCCC

Expected Output: 
4W3C2M

Explanation: 
‘W’ has the highest count, then ‘C’, then ‘M’. 
⚠️⚠️⚠️ Note:
- The input is already parsed and passed to a function.
- You need to "print" the final result (not return it) to pass the test cases.
- If the input is- “MMW”, then the expected output is "2M1W" since there is no ‘C’.
- If any of them have the same count, the output should follow this order - M, W, C.
🧐 Question🔧 Skill

Medium

Async Await Promises
Promises
Async-Await

2 mins

JavaScript
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Medium

Bitcoin prices
Axios
Promises

2 mins

JavaScript
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Medium

My Module
Scope

2 mins

JavaScript
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Medium

Promise Resolve
Promises
Async-Await

2 mins

JavaScript
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Easy

Throw, Try, Async
Promises
Async-Await

2 mins

JavaScript
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Medium

I/O cycle and main module
Event Loop

2 mins

NodeJS
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Easy

Res methods

3 mins

NodeJS
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Medium

Phases and Timers
Event Loop

2 mins

NodeJS
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Hard

Context re-renders
React Context API
Conditional Rendering
Component Lifecycle State

3 mins

React
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Medium

Hooks with Conditional Rendering
Hooks
Conditional Rendering
Event Handling

3 mins

React
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Medium

Rhyme Reducer
Reducer functions
Immutable update patterns
Lazy initialization

3 mins

React
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Hard

State Handling with Custom Hooks
Custom Hooks
Context API
Event Handling

3 mins

React
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Easy

Registration Queue
Logic
Queues

30 mins

Coding
Solve

Medium

Visitors Count
Strings
Logic

30 mins

Coding
Solve
🧐 Question🔧 Skill💪 Difficulty⌛ Time
Async Await Promises
Promises
Async-Await
JavaScript
Medium2 mins
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Bitcoin prices
Axios
Promises
JavaScript
Medium2 mins
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My Module
Scope
JavaScript
Medium2 mins
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Promise Resolve
Promises
Async-Await
JavaScript
Medium2 mins
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Throw, Try, Async
Promises
Async-Await
JavaScript
Easy2 mins
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I/O cycle and main module
Event Loop
NodeJS
Medium2 mins
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Res methods
NodeJS
Easy3 mins
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Phases and Timers
Event Loop
NodeJS
Medium2 mins
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Context re-renders
React Context API
Conditional Rendering
Component Lifecycle State
React
Hard3 mins
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Hooks with Conditional Rendering
Hooks
Conditional Rendering
Event Handling
React
Medium3 mins
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Rhyme Reducer
Reducer functions
Immutable update patterns
Lazy initialization
React
Medium3 mins
Try practice test
State Handling with Custom Hooks
Custom Hooks
Context API
Event Handling
React
Hard3 mins
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Registration Queue
Logic
Queues
Coding
Easy30 minsSolve
Visitors Count
Strings
Logic
Coding
Medium30 minsSolve
Reason #4

1200+ customers in 75 countries

customers in 75 countries
Brandon

With Adaface, we were able to optimise our initial screening process by upwards of 75%, freeing up precious time for both hiring managers and our talent acquisition team alike!


Brandon Lee, Head of People, Love, Bonito

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Reason #5

Designed for elimination, not selection

The most important thing while implementing the pre-employment JavaScript, NodeJS & React Test in your hiring process is that it is an elimination tool, not a selection tool. In other words: you want to use the test to eliminate the candidates who do poorly on the test, not to select the candidates who come out at the top. While they are super valuable, pre-employment tests do not paint the entire picture of a candidate’s abilities, knowledge, and motivations. Multiple easy questions are more predictive of a candidate's ability than fewer hard questions. Harder questions are often "trick" based questions, which do not provide any meaningful signal about the candidate's skillset.

Science behind Adaface tests
Reason #6

1 click candidate invites

Email invites: You can send candidates an email invite to the JavaScript, NodeJS & React Test from your dashboard by entering their email address.

Public link: You can create a public link for each test that you can share with candidates.

API or integrations: You can invite candidates directly from your ATS by using our pre-built integrations with popular ATS systems or building a custom integration with your in-house ATS.

invite candidates
Reason #7

Detailed scorecards & benchmarks

View sample scorecard
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Reason #8

High completion rate

Adaface tests are conversational, low-stress, and take just 25-40 mins to complete.

This is why Adaface has the highest test-completion rate (86%), which is more than 2x better than traditional assessments.

test completion rate
Reason #9

Advanced Proctoring


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About the JavaScript, NodeJS & React Assessment Test

Why you should use Pre-employment JavaScript, NodeJS & React Online Test?

The JavaScript, NodeJS & React Test makes use of scenario-based questions to test for on-the-job skills as opposed to theoretical knowledge, ensuring that candidates who do well on this screening test have the relavant skills. The questions are designed to covered following on-the-job aspects:

  • Understanding and implementing JavaScript basics such as variables, data types, operators, and control structures
  • Utilizing the features and syntax of ES6 (ECMAScript 2015) in JavaScript
  • Applying object-oriented programming principles in JavaScript
  • Handling and making asynchronous requests using APIs in JavaScript
  • Utilizing promises and understanding the concept of asynchronous programming in Node.js
  • Implementing the Node.js module system and understanding its benefits
  • Understanding the request-response lifecycle in web development
  • Building components with JSX in React
  • Understanding and implementing the React component lifecycle
  • Utilizing React Hooks and functional components to build dynamic user interfaces

Once the test is sent to a candidate, the candidate receives a link in email to take the test. For each candidate, you will receive a detailed report with skills breakdown and benchmarks to shortlist the top candidates from your pool.

What topics are covered in the JavaScript, NodeJS & React Online Test?

  • JavaScript Basics

    JavaScript Basics is a fundamental skill that measures a candidate's understanding of the core concepts of the JavaScript programming language, such as data types, variables, operators, and control flow. This skill is important to assess as it forms the foundation for writing JavaScript code effectively and efficiently.

  • JS ES6

    JS ES6 (ECMAScript 6) focuses on the modern features introduced in JavaScript, including arrow functions, destructuring, classes, modules, and enhanced object literals. Evaluating this skill is crucial as it determines a candidate's ability to leverage the latest features and syntax improvements in JavaScript.

  • JS OOPs

    JS OOPs (Object-Oriented Programming in JavaScript) evaluates a candidate's knowledge of object-oriented principles and techniques in JavaScript, such as encapsulation, inheritance, and polymorphism. This skill is important as it enables developers to design and implement robust and scalable applications using JavaScript.

  • Handling APIs

    Handling APIs measures a candidate's proficiency in interacting with external APIs (Application Programming Interfaces) using JavaScript. This skill is essential as it demonstrates the ability to fetch, send, and process data from external sources, which is often required in web development projects.

  • Asynchronous Node.js and promises

    Asynchronous Node.js and promises assess a candidate's understanding of asynchronous programming in Node.js and the usage of promises for handling asynchronous operations. This skill is crucial as Node.js is widely used for building server-side applications, and efficient handling of asynchronous operations is key to achieving good performance and responsiveness.

  • Node.js Module System

    Node.js Module System evaluates a candidate's familiarity with the module system in Node.js, which enables the organization and reusability of code through modules. This skill is important as it allows developers to leverage existing modules, maintain code separation and modularity, and facilitate the development process in Node.js.

  • Request Response Lifecycle

    Request Response Lifecycle measures a candidate's understanding of the flow and stages involved in processing HTTP requests and generating responses in web applications. This skill is crucial for web developers as it ensures they can effectively handle and manipulate HTTP requests, perform necessary actions, and generate accurate responses based on client requests.

  • Building components with JSX

    Building components with JSX evaluates a candidate's ability to create reusable and modular components in React using JSX (JavaScript XML). This skill is important as JSX simplifies the process of creating dynamic and interactive user interfaces with React, enabling developers to efficiently build complex UI structures.

  • React Component Lifecycle

    React Component Lifecycle assesses a candidate's knowledge of the various phases and methods associated with the lifecycle of a React component. This skill is crucial as it allows developers to control and manage component rendering, mounting, updating, and unmounting, thereby enhancing the performance and behavior of React applications.

  • React Hooks and functional components

    React Hooks and functional components measure a candidate's proficiency in utilizing React Hooks and building functional components in React. This skill is important as React Hooks provide a concise and efficient way to manage state, side effects, and other React features in functional components, promoting code reuse and improving overall code organization.

  • JavaScript Programming

    JavaScript Programming assesses a candidate's overall proficiency in JavaScript and their ability to apply the language to solve complex programming challenges. This skill is a comprehensive evaluation of a candidate's knowledge, covering a wide range of JavaScript concepts, syntax, and best practices to ensure they can write efficient, maintainable, and scalable JavaScript code.

  • Full list of covered topics

    The actual topics of the questions in the final test will depend on your job description and requirements. However, here's a list of topics you can expect the questions for JavaScript, NodeJS & React Test to be based on.

    Variables
    Data Types
    Operators
    Control Flow
    Functions
    Arrays
    Objects
    Scope
    Closures
    Prototype
    Inheritance
    Arrow Functions
    Template Literals
    Destructuring
    Promises
    Async/Await
    Modules
    NPM
    Express.js
    Routing
    Middleware
    AJAX
    Promises
    Callback Functions
    Streams
    Buffers
    File System
    Error Handling
    Debugging
    React Components
    JSX
    Component State
    Lifecycle Methods
    React Hooks
    Event Handling
    Forms
    Higher-Order Components
    Context API
    State Management
    React Router
    Unit Testing
    Integration Testing
    Debugging
    Functional Programming
    Data Structures
    Algorithms
    DOM Manipulation
    Event Handling
    Error Handling
    Regular Expressions
    JSON
    Fetch API
    LocalStorage
    SessionStorage
    Date and Time
    Math
    Error Handling
    Debugging
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What roles can I use the JavaScript, NodeJS & React Online Test for?

  • JavaScript Developer
  • Frontend Developer
  • Full Stack Developer
  • Node.js Developer
  • React Developer

How is the JavaScript, NodeJS & React Online Test customized for senior candidates?

For intermediate/ experienced candidates, we customize the assessment questions to include advanced topics and increase the difficulty level of the questions. This might include adding questions on topics like

  • Applying JavaScript programming concepts in problem-solving
  • Working with JavaScript events and event handling
  • Implementing and working with JavaScript data structures
  • Understanding and utilizing closures in JavaScript
  • Implementing error handling and exception management in JavaScript
  • Working with third-party libraries and frameworks in JavaScript
  • Understanding and working with RESTful APIs
  • Building and deploying applications using Node.js and Express.js
  • Implementing state management in React using Redux or Context API
  • Writing optimized and efficient JavaScript code

The coding question for experienced candidates will be of a higher difficulty level to evaluate more hands-on experience.

Singapore government logo

The hiring managers felt that through the technical questions that they asked during the panel interviews, they were able to tell which candidates had better scores, and differentiated with those who did not score as well. They are highly satisfied with the quality of candidates shortlisted with the Adaface screening.


85%
reduction in screening time

JavaScript, NodeJS & React Hiring Test FAQs

Can I combine multiple skills into one custom assessment?

Yes, absolutely. Custom assessments are set up based on your job description, and will include questions on all must-have skills you specify. Here's a quick guide on how you can request a custom test.

Do you have any anti-cheating or proctoring features in place?

We have the following anti-cheating features in place:

  • Non-googleable questions
  • IP proctoring
  • Screen proctoring
  • Web proctoring
  • Webcam proctoring
  • Plagiarism detection
  • Secure browser
  • Copy paste protection

Read more about the proctoring features.

How do I interpret test scores?

The primary thing to keep in mind is that an assessment is an elimination tool, not a selection tool. A skills assessment is optimized to help you eliminate candidates who are not technically qualified for the role, it is not optimized to help you find the best candidate for the role. So the ideal way to use an assessment is to decide a threshold score (typically 55%, we help you benchmark) and invite all candidates who score above the threshold for the next rounds of interview.

What experience level can I use this test for?

Each Adaface assessment is customized to your job description/ ideal candidate persona (our subject matter experts will pick the right questions for your assessment from our library of 10000+ questions). This assessment can be customized for any experience level.

Does every candidate get the same questions?

Yes, it makes it much easier for you to compare candidates. Options for MCQ questions and the order of questions are randomized. We have anti-cheating/ proctoring features in place. In our enterprise plan, we also have the option to create multiple versions of the same assessment with questions of similar difficulty levels.

I'm a candidate. Can I try a practice test?

No. Unfortunately, we do not support practice tests at the moment. However, you can use our sample questions for practice.

What is the cost of using this test?

You can check out our pricing plans.

Can I get a free trial?

Yes, you can sign up for free and preview this test.

I just moved to a paid plan. How can I request a custom assessment?

Here is a quick guide on how to request a custom assessment on Adaface.

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