A few questions about unit tests

Question

Two questions about unit tests.

• I write unit tests for while, as a rule, they are usually test classes that I already wrote. I recently read an article article (remember the old article) that says: you have to write unit tests before you start writing your code.

  Does anyone really follow this methodology? It seems like a good idea on paper, but in practice it?

• Do you have to write unit tests to find out how your method handles bad / malicious input? Obviously, you would like to write tests against functions that are specifically designed to handle "user" input, to see how it handles bad / malicious data, but what about functions that should never have passed this type of data? At what point do you draw the line?

Answer 1

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