30+ Impelsys Interview Questions and Answers

There are three types of errors in PHP: syntax errors, runtime errors, and logical errors.

• Syntax errors occur when the code violates the rules of PHP syntax.

• Runtime errors occur during the execution of the script, such as division by zero or accessing undefined variables.

• Logical errors do not cause the script to terminate, but they produce incorrect results or unexpected behavior.

To display an image from a database in a PHP view page, retrieve the image as a blob and output it with appropriate headers.

• Retrieve the image data from the database as a blob.

• Set the appropriate content-type header for the image format.

• Output the image data to the response body.

To prepare a report and share it with stakeholders, follow these steps:

• Gather all relevant data and information

• Organize the report structure and format

• Include an executive summary highlighting key findings

• Present the test objectives, methodology, and scope

• Provide detailed test results and analysis

• Include performance metrics and benchmarks

• Highlight any issues or bottlenecks discovered

• Offer recommendations for improvement

• Ensure the report is clear, concise, and visually appeali...read more

Server-side challenges and troubleshooting techniques for a Senior Performance Test Engineer

• Identifying and resolving performance bottlenecks

• Optimizing server response time

• Handling high traffic and load balancing

• Troubleshooting server crashes and errors

• Monitoring server resources and performance metrics

• Analyzing server logs and error messages

• Identifying and resolving database performance issues

• Implementing caching mechanisms for improved performance

PHP program to print *(stars) in pyramid shape

• Use nested for loops to print the pyramid shape

• The outer loop controls the number of rows

• The inner loop controls the number of stars to print in each row

• Use a combination of spaces and stars to create the pyramid shape

Hits per second measures the number of requests made to a system per second, while throughput measures the amount of data transferred per unit of time.

• Hits per second focuses on the number of requests made to a system per second.

• Throughput focuses on the amount of data transferred per unit of time.

• Hits per second is a measure of the system's capacity to handle requests.

• Throughput is a measure of the system's efficiency in transferring data.

• Hits per second can be used to ident...read more

Some challenges faced in JMeter

• Configuring JMeter for distributed testing

• Handling dynamic parameters in requests

• Analyzing and interpreting test results

• Simulating realistic user behavior

• Identifying and resolving performance bottlenecks

PHP provides a variety of pre-defined functions for string manipulation.

• strlen() - returns the length of a string

• str_replace() - replaces all occurrences of a search string with a replacement string

• substr() - returns a part of a string

• strtolower() - converts a string to lowercase

• strtoupper() - converts a string to uppercase

In the test planning phase, a Senior Performance Test Engineer will define the objectives, scope, and approach of the performance testing.

• Define the objectives and goals of the performance testing

• Identify the scope of the performance testing

• Determine the approach and strategy for conducting performance tests

• Identify the performance testing tools and technologies to be used

• Define the performance testing environment and infrastructure requirements

• Identify the performance test s...read more

Yes, I have knowledge on Gatling and Neoload.

• I have experience using Gatling and Neoload for performance testing.

• I am familiar with the features and functionalities of both tools.

• I have used Gatling to simulate high loads and measure system performance.

• I have used Neoload to create realistic user scenarios and analyze performance metrics.

• I am proficient in scripting and configuring tests using Gatling and Neoload.

ng-template, ng-content, and ng-container are Angular structural directives used for template rendering and content projection.

• ng-template is used to define a template that can be rendered conditionally or multiple times.

• ng-content is used for content projection, allowing the insertion of content from a parent component into a child component.

• ng-container is a grouping element that doesn't interfere with styles or layout, often used to wrap multiple elements for structural pu...read more

I follow PSR coding standards and adhere to best practices.

• I follow PSR-1 and PSR-2 coding standards.

• I use meaningful variable and function names.

• I write clean and readable code.

• I use proper indentation and spacing.

• I avoid using global variables.

• I use comments to explain complex code.

• I adhere to best practices for security and performance.

• For example, I always use prepared statements to prevent SQL injection attacks.

PHP supports all major Object-Oriented Programming concepts including classes, objects, inheritance, encapsulation, and polymorphism.

• Classes: PHP allows you to define classes using the 'class' keyword.

• Objects: You can create objects of a class using the 'new' keyword.

• Inheritance: PHP supports inheritance where a class can inherit properties and methods from another class.

• Encapsulation: PHP allows you to restrict access to certain properties and methods using access modifiers ...read more

Third-party services can be managed by integrating them into the MVC framework using libraries or APIs.

• Use libraries or APIs provided by the third-party service to interact with it within the MVC framework.

• Create service classes or components to encapsulate the logic for interacting with the third-party service.

• Utilize dependency injection to inject the third-party service dependencies into the controllers or models.

• Handle errors and exceptions that may arise from interaction...read more

Abstract classes and interfaces are used to define common methods and properties for classes to implement.

• Abstract classes cannot be instantiated and can contain both abstract and non-abstract methods.

• Interfaces only contain method signatures and constants, and classes can implement multiple interfaces.

• Abstract classes are useful for creating a base class with common functionality, while interfaces are useful for defining a contract for classes to follow.

• Example: abstract cla...read more

Yes

• Yes, I have experience working on Chaos testing.

• Chaos testing involves intentionally injecting failures and faults into a system to test its resilience and stability.

• I have designed and executed chaos experiments to simulate real-world scenarios and identify potential weaknesses in the system.

• Examples of chaos testing techniques I have used include randomly killing processes, introducing network latency, and inducing resource exhaustion.

• By conducting chaos testing, I have ...read more

Custom pipes in Angular are used to transform data in templates.

• Custom pipes are created using the @Pipe decorator in Angular.

• To use a custom pipe in HTML, you need to include it in the declarations array of the NgModule.

• You can pass parameters to custom pipes in HTML using the pipe symbol (|).

• Example: {{ value | customPipe:param1:param2 }}

Create a screen with modal design

• Use a modal component to display content on top of the main screen

• Include a close button to dismiss the modal

• Design the modal with a semi-transparent background to focus on the content

• Ensure the modal is responsive and works on different screen sizes

The most used application on my phone is Instagram because I enjoy sharing photos and keeping up with friends and influencers.

• I use Instagram to share photos and videos with my friends and followers

• I enjoy keeping up with the latest trends and updates from influencers and celebrities

• I use Instagram to discover new products and brands through sponsored posts and ads

Distinct returns unique values while group by groups and aggregates data based on a column.

• Distinct returns only unique values from a single column.

• Group by groups and aggregates data based on a column.

• Distinct can be used to count the number of unique values in a column.

• Group by can be used to group data by a column and perform aggregate functions like sum, count, avg, etc.

• Distinct is used to remove duplicates from a column.

• Group by is used to group data based on a column an...read more

Design patterns are reusable solutions to common software development problems.

• Design patterns provide proven solutions to recurring problems in software development.

• They help in creating code that is more flexible, reusable, and maintainable.

• Some common design patterns include Singleton, Factory, Observer, and Decorator.

• Singleton pattern ensures that only one instance of a class is created.

• Factory pattern provides a way to create objects without specifying the exact class of...read more

Handle errors in fetching API calls by implementing error handling mechanisms.

• Use try-catch blocks to catch errors during API calls

• Implement error handling logic in the catch block to handle different types of errors

• Display user-friendly error messages to inform users about the issue

• Use HTTP status codes to identify the type of error (e.g. 404 for not found)

• Implement retry mechanisms for temporary network issues

Special characters in columns can be handled by replacing or removing them.

• Identify the special characters in the column

• Replace the special characters with a suitable alternative

• Remove the special characters if they are not necessary

• Use regular expressions to handle complex special characters

• Ensure that the data type of the column is appropriate

An autoloader is a function that automatically loads classes when they are needed in a PHP script.

• Autoloaders eliminate the need to manually include class files.

• They use naming conventions to locate and load class files.

• Autoloaders can be registered using spl_autoload_register() function.

• Composer provides a default autoloader for PHP projects.

Yes, I have automation testing experience.

• I have worked on various automation testing tools such as Selenium, Appium, and JUnit.

• I have developed automated test scripts for web applications, mobile applications, and APIs.

• I have experience in creating test frameworks and implementing continuous integration and delivery pipelines.

• I have used programming languages like Java, Python, and JavaScript for automation testing.

• I have worked on both functional and performance testing aut...read more

ForkJoin is an operator in Angular that allows for parallel execution of multiple observables.

• ForkJoin combines the values from multiple observables and emits them as an array when all observables complete.

• It waits for all observables to complete and then emits the combined result.

• Example: forkJoin([observable1, observable2]).subscribe(result => console.log(result));

Arrow functions are concise and do not bind their own 'this' value, while regular functions have their own 'this' value and can be used as constructors.

• Arrow functions have a more concise syntax compared to regular functions.

• Arrow functions do not have their own 'this' value, they inherit it from the parent scope.

• Regular functions have their own 'this' value, which can be useful for object-oriented programming and constructor functions.

Wildcard routes in Angular allow for handling unknown routes and redirecting to a default route.

• Wildcard route is denoted by '**' in the route configuration.

• It is typically used at the end of the route configuration to handle unknown routes.

• Example: { path: '**', redirectTo: '/404' }

PHP program to sort array of strings

• Use the built-in sort() function

• Pass the array as argument to the sort() function

• Use the SORT_STRING flag to sort the array as strings

The .htaccess file is used to configure web server settings for a specific directory.

• Used to set up redirects and rewrite rules

• Can restrict access to certain files or directories

• Can set custom error pages

• Can enable/disable certain features like caching or compression

ES6 features are modern JavaScript enhancements that improve code readability and efficiency.

• Arrow functions for concise syntax: const add = (a, b) => a + b;

• Let and const for block-scoped variables: let x = 5; const y = 10;

• Template literals for string interpolation: const name = 'John'; console.log(`Hello, ${name}!`);

• Destructuring assignment for easily extracting values from arrays or objects: const { firstName, lastName } = person;

• Spread syntax for merging arrays or objects:...read more

Shallow copy only copies the references of nested objects, while deep copy creates new copies of nested objects.

• Shallow copy creates a new object but does not create copies of nested objects.

• Deep copy creates a new object and also creates copies of nested objects.

• Shallow copy is faster and more memory efficient, but changes to nested objects affect both original and copied objects.

• Deep copy is slower and consumes more memory, but changes to nested objects do not affect the or...read more

Subject vs BehaviourSubject in Angular

• Subject is a basic observable that emits values to subscribers

• BehaviourSubject is a type of Subject that stores the latest value and emits it to new subscribers

• BehaviourSubject requires an initial value when created

DBMS normalisation and keys

• Normalization is the process of organizing data in a database to reduce redundancy and dependency

• Keys are used to uniquely identify a record in a table

• Primary key is a unique identifier for a record

• Foreign key is a field in a table that refers to the primary key of another table

• Composite key is a combination of two or more fields that uniquely identify a record

Angular Universal is a server-side rendering (SSR) solution for Angular applications.

• Angular Universal allows rendering Angular applications on the server-side, improving performance and SEO.

• It generates static HTML on the server and sends it to the client, reducing the initial load time.

• Angular Universal supports dynamic rendering, allowing the server to respond with fully rendered pages for better user experience.

• It enables sharing code between the server and the client, re...read more

Right join and right outer join are the same thing.

• Right join and right outer join are interchangeable terms.

• Both return all the rows from the right table and matching rows from the left table.

• If there is no match, the result will contain NULL values for the left table columns.

• Used to combine data from two tables based on a common column.

• Syntax: SELECT * FROM table1 RIGHT JOIN table2 ON table1.column = table2.column;