Introduction

During any kind of software development, a Quality Assurance process is required if the code quality is concerned. During any human endeavor, including programming, mistakes (bugs) are unavoidable. So the main task of the quality assurance (QA) engineer, sometimes also referred to as a tester, is to identify and raise issues so that they can be fixed in a timely manner. As software types vary greatly so does the QA processes and tools used to test them. In this course we will take a look on various types of testing (regression, smoke, etc) and learn when and where they are applied. We will also learn how to test mobile, web and desktop applications and identify which tests can be automated and how to go about doing that.

What is BDD and TDD?

In the software engineered world you’ll hear the terms BDD and TDD casually tossed around. BDD stands for Behavior Driven Development and TDD stands for Test Driven Development. TDD encourages writing tests before starting the development of a feature. So at the first run the test obviously fails. After the feature is developed the test is run again and it should pass this time. Consequently, the codebase will have high test coverage which is a good software engineering practice. As you can see TDD is a developer-centric testing approach and used for writing unit tests.
BDD on the other hand, describes a feature or a functionality in a human-readable language called Gherkin, understandable to various stakeholders involved in the project. In practice we use IDE plugins to have nicely formatted scenarios in Gherkin and runnable methods in Cucumber for Java or Behave for Python.

QA Basics

Depending on the software under the test different tools and methodologies are used for testing but there are some fundamental testing principles shared among various testing approaches. Let’s learn about those principles.
Testing reveals the presence of defects, not their absence
No tester can assure that the software on have doesn’t have any issues. Perfection is hardly achievable in real life. Hence, as testers, we do our best to find and document bugs but we cannot say with absolute confidence that the software under test is bug free.
Exhaustive testing is impossible
Simply put, you cannot test every possible scenario in which the product under test can break. That’s practically not feasible. Also, it doesn’t make sense because you can gain sufficient confidence in performance and functionality of your software by strategically covering with tests the most important aspects of it. Meanwhile, automated testing tools exist that can generate a huge number of test cases thus giving you enough confidence in your tests.

Web UI testing

In web UI testing you, as a tester, try to make sure that the elements on the webpage function properly, are placed correctly, and look as intended. To test the functionality of web elements you would normally try interacting with them like clicking a button, choosing an option from a drop-down, etc and see if they are behaving correctly. The correct placement is easy to check by a visual inspection of the page. Meanwhile, to have a correct look and feel certain CSS attributes should be present. All the described inspections can be done manually though it can be error prone and time consuming, especially if there are many pages to test. An alternative is to automate the testing process by writing tests that can run periodically and perform the mentioned tasks. Arguably the most popular tool for automated UI tests is Selenium but another tool called Cypress is also getting popular in recent years.

API Testing

Practically all modern web and mobile applications make some kind of API calls to the other servers on the web. Via API requests and responses an application interacts with back-end and third-party services to perform various tasks like user authentication, data retrieval, sending notifications and so on. So correctly functioning API calls are crucial for the application's health. Though you can check an API call response on the UI side by trying to log into the system or validate data retrieved from a 3-rd party service, it is faster to test the underlying calls directly. Here’s when API testing comes into play. Commonly used API requests are GET, POST, PUT, and DELETE. Every API call consists of a request endpoint, header and body. The body content is usually JSON or XML. The most popular API testing tool is Postman. It lets us make all kinds of API requests and observe the responses. Some advanced features of Postman include Environments, Scripts, Collections, Mock Servers and more. Besides Postman, we can use special programming language libraries like Python’s requests library intended for working with the APIs. This gives us more flexibility and deeper automation test coverage.

Mobile testing

Among the various mobile application testing tools, Appium; It does not require SDK includes or the need to recompile. With iOS, Android and Windows apps.
Its task relies on client/server architecture (client/server architecture). An immediate advantage of the client/server architecture is that tests can be written on the local machine.