Development with Python

Useful TDD Concepts and Rules Of Thumb

Test Isolation and Global State

Different tests shouldn’t affect one another. This means we need to reset any per‐

manent state at the end of each test. Django’s test runner helps us do this by creating

a test database, which it wipes clean in between each test. (See also

Working State to Working State (aka The Testing Goat vs. Refactoring Cat)

Our natural urge is often to dive in and fix everything at once … but if we’re not

careful, we’ll end up like Refactoring Cat, in a situation with loads of changes to our

code and nothing working. The Testing Goat encourages us to take one step at a

time, and go from working state to working state.

YAGNI

You ain’t gonna need it! Avoid the temptation to write code that you think

might

useful, just because it suggests itself at the time. Chances are, you won’t use it, or

you won’t have anticipated your future requirements correctly. See

for

one methodology that helps us avoid this trap.

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Chapter 6: Getting to the Minimum Viable Site