The Coder Cafe

The Coder Cafe

Home
Programming
Testing
Distributed Systems
Reliability
Systems
Beyond Code
Inner Brew
📌 Index
💬 Discord

Testing

Property-Based Testing
Traditional tests don’t guarantee a bug-free system; a passing test only confirms that the tested scenario behaves as expected.
 • 
Teiva Harsanyi
Eventually Green Tests (April Fool’s Joke)
With enough time, 97% of failing tests will eventually pass or become irrelevant.
 • 
Teiva Harsanyi
3
Code Coverage
When a measure becomes a target, it ceases to be a good measure.
 • 
Teiva Harsanyi
Avoiding Logic in Tests
A test shouldn't mirror the code logic it’s meant to validate.
 • 
Teiva Harsanyi
3
Test-Driven Development (TDD)
TDD is a personal choice, not a measure of test quality.
 • 
Teiva Harsanyi
4
Test Behavior, Not Implementation
By focusing on behavior, our test remains the same, unaffected by changes to the underlying implementation.
 • 
Teiva Harsanyi
Unit Tests As Documentation
Unit tests are always in sync with the code, making them a powerful tool for up-to-date documentation.
 • 
Teiva Harsanyi
1
Line vs. Branch Coverage
In this example, branch coverage will detect that our test only covers 50% of the possible branches.
 • 
Teiva Harsanyi
1
10 Unit Test Properties
Narrow in scope, validating the correctness of individual pieces of code rather than the correctness of the system as a whole.
 • 
Teiva Harsanyi
Common Arguments Against Unit Tests
Skipping unit tests might seem like a time-saver, but it often leads to greater problems later.
 • 
Teiva Harsanyi
© 2025 Teiva Harsanyi
Privacy ∙ Terms ∙ Collection notice
Start writingGet the app
Substack is the home for great culture