Forms & validation · level 3 of 5 · Terra Supply
The happy path proves an order can be placed. Only the unhappy path proves the wrong order cannot be.
Go through Terra Supply checkout with an invalid card number (1234) and prove the order is refused.
Fill in the other fields correctly, name, email and address, so the card is the only thing wrong.
A checkout test that only ever pays with a valid card cannot tell working validation from none at all.
We break each one in a copy of the app. Your test has to fail on every copy.