SDET

Unit testing is the process of testing a single unit of code in an isolated manner. The unit of code can be a method, a class, or a module. Unit testing aims to focus on the smallest building blocks of code to get confidence to combine them later to produce fully functioning software.

In software, many errors occur near the edges of the range of the data values. For example, when the programmer uses the greater-than operator (>) instead of the greater-than-or-equal-to (>=) operator, it causes the off-by-one indexing error.

A constructor is automatically called when an object is first created. Similarly, when an object is destroyed, a function called a destructor automatically gets called. A destructor has the same name as the constructor (which is the same as the class name) but is preceded by a tilde.

A copy constructor is a member function that initializes an object using another object of the same class.

A test is a good candidate for automation under the following conditions.

1) The test is repeatable.
2) The feature under the test doesn’t change its behavior frequently.
3) It’s time-consuming for a human tester.
4) The test involves complicated calculations.
5) The test ensures the previous functionality didn’t break after a new change.

Here are some of the best practices a software development and testing team should use to ensure quality software:

1. Decide what to automate
  It’s not possible or practical to automate certain tests, such as usability, accessibility, exploratory testing, or non-repetitive test cases that frequently change.

2. Assign test cases based on skill and experience
  When dividing test cases, take into account the skills and experience of the tester and the complexity and severity of the feature under test.

3. Remove uncertainty
  The whole goal of test automation is to have reliable, accurate, consistent tests that provide helpful feedback to the tester. If the tests fail due to bugs in the test itself, or if they give false positives, then the ROI on test automation starts decreasing.

4. Choose the right frameworks and tools
  There are many tools to perform automation testing. Picking the wrong tool for the test at hand will waste time and provide false confidence in releasing software that may fail in production.

Selenium is not a single tool or a framework. It is a suite of tools that work with each other or in isolation to provide different types of automation testing. Here are the four major components of Selenium.

Selenium provides the following advantages, which make it an excellent automated testing framework:

1) It is free and open-source software with a large user base and supports providing community.

2) It has cross-browser compatibility and supports multiple browsers like Google Chrome, Mozilla Firefox, Internet Explorer, Edge, Opera, Safari, etc.

3) It supports multiple operating systems such as Windows, Linux, macOS, etc.

4) It facilitates the usage of multiple programming languages including Scala, Ruby, Python, PHP, Perl, Java, Groovy, C#, etc.

5) It provides support for distributed testing as well.

XPath, also defined as XML-Path (Extensible Markup Language Path), is a language used to query XML documents and provide functionalities like locating elements in Selenium by iterating through each element in a webpage. In XPath, data is stored in a key-value pair format similar to an HTML tag. It uses a single slash, i.e. ‘ / ’ for creating an absolute path, and a double slash, i.e. ‘ // ’ for creating a relative path for an element to be located on a webpage.

Given two strings, ‘A’ and ‘B’. Return the shortest super sequence string ‘S’, containing both ‘A’ and ‘B’ as its subsequences. If there are multiple answers, return any of them.