Testing in React.js and Flask
Published: 2023-12-18 07:02:01

## A Practical Dive into System Testing for Junior Developers

**Introduction**

As I approach the end of my software engineering bootcamp, I've realized that testing is a crucial aspect of building reliable applications. I used to be a bit intimidated by the idea of testing, especially since we had a lot of tests written for us during our coding challenges. Looking at those test files was overwhelming at first, but as I've learned more about it, I can't stress enough how important it can be the larger our projects scale up. As we are getting ready to present our final projects, a full stack application, I thought it'd be super helpful to talk about something that's really important but not always highlighted enough: System Testing. We've heard a bit about Unit Testing, and it will probably be the most relevant to us as junior developers, however for bigger projects such as ours, we are going to be focusing on System Testing!

## Why Testing Matters
Before we jump into testing, let's understand why it's essential. Think of testing as a safety net for your code. It helps you catch bugs early in the development process, ensuring that your application behaves as expected. Here are a few key reasons why testing is so important:

**1. Preventing Bugs**
Testing allows you to identify and fix issues before they reach users.

**2. Confidence in Code Changes**
When you make changes or add new features, tests provide reassurance that existing functionality still works.

**3. Collaboration and Maintenance**
Tests serve as documentation for your code. They help you and your team understand how different parts of the application should work. Plus, they make it easier to maintain and improve your code over time.


**Understanding Different Types of Testing**
Before we discuss System Testing, let's break down the different types of testing we've come across:

1. _Unit Testing_: Testing individual units or components.
2. _Integration Testing_: Ensuring different modules work together.
3. _System Testing_: A comprehensive testing of the complete and fully integrated software application.
4. _Acceptance Testing_: Verifying the application meets business requirements. 

**Why System Testing Is Great For Our Projects**
System Testing is a holistic approach that examines the entire application in a scenario that mimics real-world use. It's not just about checking individual parts but ensuring that everything works together seamlessly--an aspect crucial for the success of our capstone projects.

Why Focus on System Testing?

- **Comprehensive Coverage**: It evaluates the application's overall functioning and performance.
- **User Perspective**: System tests simulate real user experiences, covering functional and non-functional requirements.
- **Risk-Mitigation**: Helps identify issues that might not be evident in unit or integration tests.

System Testing in Practice: A Full Stack Application Example
Let's consider an example relevant to our full stack project, a front-end built with React, and a back-end using Flask, and a database.

**System Test Scenario: User Registration and Login Flow**

1. **Test Objective**: Verify that a new user can register and log in to the application.
2. **Steps:**

- Access the application's registration page.
- Fill in the registration form with user details and submit.
- Check if the user is directed to a confirmation page or receives a confirmation email.
-Log out and then navigate to the login page
- Log in with the newly created credentials
-Verify that the user accesses the dashboard after login.

3.**Tools:** Tools like Selenium or Cypress can automate these steps, simulating a user's actions in a browser.

Writing a System Test (Pseudocode):
```python
# Example of a system test script in pseudocode
# using a tool like Selenium or Cypress

navigate_to("registration_page")
fill_form({"username": "newuser", "password": "password123"})
submit_form()
assert_on_page("confirmation_page")

logout()
navigate_to("login_page")
login({"username": "newuser", "password": "password123"})
assert_on_page("dashboard")
```
Selenium and Cypress are among the most common and widely used tools in the development space for browser automation and system testing. They are popular for reasons such as

#### Selenium

- **Versatility**: Selenium supports multiple programming languages like Java, C#, Python, Ruby, and JavaScript, making it a versatile choice for various development teams.
- **Browser Compatibility**: It works across different browsers like Chrome, Firefox, Internet Explorer, and Safari.
- **Community and Support**: Being one of the oldest tools in the market, it has a large community and extensive support resources.
- **Integration with Other Tools**: Selenium integrates well with other testing frameworks and Continuous Integration (CI) tools.

#### Cypress

- **Modern Framework**: Cypress is built for modern web applications and offers a more developer-friendly experience.
- **Real-time Testing**: It allows developers to see tests running in real time, which can be beneficial for debugging.
- **Automatic Waiting**: Cypress automatically waits for commands and assertions, reducing the flakiness of tests.
- **Rich Set of Features**: It provides features like time travel, snapshots, and network traffic control, making testing more efficient.

In addition to Selenium and Cypress, there are other tools like Puppeteer, WebDriverIO, and Playwright that are also gaining traction in the development community for similar purposes. The choice of tool often depends on the specific needs of the project and the familiarity of the development team with the tool.

## Best Practices in System Testing
When conducting system testing, there are several best practices to follow:

- **Start Early and Test often:** Incorporate system testing early in the development cycle. This helps in identifying and fixing issues sooner.
- **Create Realistic Test Scenarios:** Simulate real-world scenarios that closely mimic user behavior and environments.
- **Prioritize Tests:** Focus on critical paths in your application. Not all tests are equally important.
- **Automate Where Possible:** Automate repetitive and time-consuming tests to improve efficiency.
- **Keep Tests Maintainable:** Write clear, concise, and well-documented tests. This makes maintenance easier as your application evolves.
- **Review and Refine:** Regularly review your test cases and update them as the application changes.


## Integrating System Testing into Your Workflow
As junior developers stepping out into the field, especially with a freshly completed project that we may continue to work on and improve, understanding and implementing System Testing provides us with a more broad perspective on our applications' functionality.  While Unit Testing remains a fundamental skill for us, System Testing elevates our testing approach to encompass the entire application, ensuring we deliver a product that not only works in parts but excels as a whole.

Learning System Testing now is a great way to get ready for the real world of software development. It's a skill that'll help us not just as coders but as developers who can create cool, user-friendly applications.


**Extra Resources**
1._integration testing documentation_ https://www.guru99.com/testing-documentation.html
2._What is System Testing - an ultimate beginners guide_
https://www.softwaretestinghelp.com/system-testing/
3. _Selenium Tutorial: A Complete Guide on Selenium Testing_
https://www.lambdatest.com/selenium