How are tests different from validation?

Question

Ruby on Rails

Why do I need tests? When there is validation, why do we need tests?

Answer 1

Validation is an additional feature of the framework that allows you to check whether the dressed data meets your expectations. For example - that the user will enter a password of 8 characters, and not of 3, or that the site address " wwdi.ru " is correct, but "yaya//yvayva,.," is incorrect. Tests, on the other hand, are a tool for checking how your code works correctly, for example, that after login, the user is sent to the dashboard, and with correct registration, a new user appears.

Answer 2

I don't know why you need tests. You can replace them with validation. In our villages, this is not yet possible.

Answer 3

It's hard to say how they differ, it's like asking: what is the difference between blue and soft.
Validation involves checking data with a positive or negative result.
Assertions are similar to validations, but must throw exceptions, unlike validations.
Tests involve checking the business logic of the application.