Web Scraping30 min read
Testing Scrapers
Learn how to test scraping logic using saved HTML and unit tests so site changes don’t silently break your scrapers.
David Miller
December 17, 2025
1.1k26
Websites change often.
Your scraper may break without warning.
Testing helps catch this early.
Key idea
Separate:
- fetch logic
- parse logic
Then test parsing with saved HTML.
Example: parse function
from bs4 import BeautifulSoup
def parse_title(html):
soup = BeautifulSoup(html, "html.parser")
return soup.select_one("h1").text.strip()
Test with sample HTML
def test_parse_title():
html = "<html><h1>Hello</h1></html>"
assert parse_title(html) == "Hello"
test_parse_title()
Save real HTML for tests
with open("sample.html") as f:
html = f.read()
assert parse_title(html) == "Expected Title"
Why this helps
- no network needed
- fast tests
- safe against site downtime
Graph: test flow
flowchart LR
A[HTML Sample] --> B[Parse Function]
B --> C[Expected Data]
Remember
- Always test parsing logic
- Keep sample HTML files
- Tests save hours of debugging
#Python#Advanced#Testing