Happy Path
ELI5 — The Vibe Check
The happy path is when everything goes perfectly — the user types the right thing, the API responds correctly, nothing breaks. Most people test the happy path first. But bugs hide in the unhappy paths, which is why you also need to test what happens when things go wrong.
Real Talk
The happy path refers to the default, error-free execution flow through a system where all inputs are valid and all external dependencies behave as expected. Testing the happy path is necessary but insufficient — edge cases and error paths must also be tested.
When You'll Hear This
"The happy path works fine, but what happens when the API is down?" / "Don't just test the happy path — test what happens when the user leaves fields blank."
Related Terms
Corner Case
A corner case is like an edge case but even weirder — it's when MULTIPLE unusual things happen at the same time. An edge case is a weird input.
Edge Case
Edge cases are the weird, extreme, or unexpected inputs that trip up your code. What if someone types 0 for age?
Smoke Test
A smoke test is the most basic sanity check: does the app even start? Does it not immediately crash?
Test Case
A test case is one specific scenario you want to check. 'Does the login work with a correct password?' — that's a test case.