Python Setup Guide for Beginners: Install Python, Create a Virtual Environment, and Run pytest

Before you can start test automation with Python, you need a working environment. “I installed it but nothing runs” and “what even is venv?” are the two most common blockers for beginners. This guide walks through every step — on both Windows and Mac — one command at a time.

📌 Who This Article Is For

📖 What You’ll Be Able to Do After This Guide

I have worked on test automation across multiple projects using Python with Selenium, Playwright, and pytest.
When onboarding new team members, I noticed the same setup mistakes coming up every single time.
This guide is written from that experience to proactively address the exact points where beginners get stuck.

Setup Overview

① Install Python

Windows

1. Download the installer from the Python official site
Open a browser, go to python.org/downloads, and download the Python 3.12.x installer. The very latest version occasionally has libraries that haven’t fully caught up, so the most recent stable 3.12.x release is a safe choice.

2. Run the installer
Launch the downloaded .exe file. Before clicking anything, check the following on the very first screen.

3. Open Command Prompt after installation
Search for “cmd” in the Start menu, or press Windows + R, type cmd, and press Enter.

Mac

Mac ships with an old Python version, so it’s best to install a newer one separately for test automation.
Using Homebrew is the most straightforward approach. If Homebrew feels daunting, the official installer at python.org/downloads works equally well.

1. Install Homebrew if you don’t have it
Open Terminal (Finder → Applications → Utilities → Terminal) and run:

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

2. Install Python via Homebrew

brew install python

② Verify the Installation

Once installation is complete, confirm it from the command line.

# Run in Command Prompt (Windows) or Terminal (Mac)
python --version

Expected output:

Python 3.12.3

Also verify pip (Python’s package manager):

pip --version
# or on Mac if needed:
pip3 --version

Expected output:

pip 24.0 from /usr/local/lib/python3.12/site-packages/pip (python 3.12)

③ Create a Virtual Environment with venv (Important)

What is venv?

venv is Python’s built-in tool for creating isolated environments per project.

Without it, you run into version conflicts like this:

If both projects share a single global Python install, updating selenium for one project breaks the other.
Virtual environments keep each project’s dependencies completely separate.

Creating Your Virtual Environment

1. Create a project folder and navigate into it

# Create the folder
mkdir my-test-project

# Move into it
cd my-test-project

2. Create the virtual environment

python -m venv venv
# On Mac if python3 is required:
# python3 -m venv venv

A venv folder will be created containing the isolated environment files.
At this point, your project structure looks like this:

my-test-project/
├── venv/              ← virtual environment (do NOT commit to Git)
├── test_sample.py     ← test file (created later)
└── requirements.txt   ← library list (created later)

3. Activate the virtual environment

# Windows (Command Prompt)
venv\Scripts\activate

# Windows (PowerShell)
venv\Scripts\Activate.ps1

# Mac / Linux
source venv/bin/activate

Once activated, your prompt will show (venv) at the start:

(venv) C:\Users\yourname\my-test-project>   # Windows
(venv) yourname@mac my-test-project %       # Mac

While (venv) is visible, the virtual environment is active.
Make it a habit to activate before starting work each time.

4. To deactivate

deactivate

④ Install Libraries with pip

pip is Python’s package manager. Let’s install the libraries commonly used in test automation.
Always make sure your virtual environment is activated (look for (venv)) before running pip.

First, upgrade pip itself (recommended)

python -m pip install --upgrade pip

# pytest (test framework)
pip install pytest

# Selenium (browser automation)
pip install selenium

# Playwright (modern browser automation)
pip install playwright
playwright install  # installs the browser binaries

# requests (API testing)
pip install requests

To see what’s installed in your current environment:

pip list

Managing Dependencies with requirements.txt

When working with a team or reproducing an environment, store your library list in a requirements.txt file.

# Export the current environment to a file
pip freeze > requirements.txt

# Reproduce the environment from the file
pip install -r requirements.txt

⑤ Set Up VS Code

Any editor works, but VS Code (Visual Studio Code) is widely used for Python test automation. It’s free, well-supported, and integrates cleanly with venv.

Installation and Recommended Extensions

Download VS Code from code.visualstudio.com. After installing, add the following extensions (use the Extensions icon in the left sidebar to search and install).

Point VS Code to Your Virtual Environment

After opening your project folder in VS Code, click the Python version shown in the bottom-right corner and select your venv’s Python interpreter.

# Alternatively: open the Command Palette with Ctrl+Shift+P (Mac: Cmd+Shift+P)
# → select "Python: Select Interpreter"
# → choose ./venv/Scripts/python.exe (Windows) or ./venv/bin/python (Mac)

⑥ Run a Smoke Test

Let’s confirm the whole setup is working end to end.

Running Your First pytest

Create a file called test_sample.py in your project folder and paste the following:

# test_sample.py
def test_addition() -> None:
    assert 1 + 1 == 2

def test_string() -> None:
    assert "hello".upper() == "HELLO"

Run it from the terminal (with your virtual environment activated):

# Standard way
pytest test_sample.py -v

# Alternative (useful if pytest command isn't found)
python -m pytest test_sample.py -v

Expected output:

========================= test session starts ==========================
collected 2 items

test_sample.py::test_addition PASSED                            [ 50%]
test_sample.py::test_string   PASSED                            [100%]

========================== 2 passed in 0.12s ==========================

If you see “2 passed” — your environment is ready. 🎉

7 Common Pitfalls in Python Environment Setup

Frequently Asked Questions (FAQ)

Summary

With your environment set up, the next step is learning how to write actual tests — head to the pytest guide or Selenium setup article linked above.

Setup only needs to happen once. After that, you can focus entirely on writing code. Take it one step at a time.