interface vs functions for mocking

[Amarjeet Anand]

Hi

While writing unit test, what should be the preferred way to mock an external(database, http...) call, function based approach or interface based approach?

I don't understand when to use function way and when to use interface way. Which one is more idiomatic Golang way if I am writing my web server from scratch?

[Volker Dobler]

On Saturday, 9 May 2020 09:57:50 UTC+2, Amarjeet Anand wrote:

While writing unit test, what should be the preferred way to mock an external(database, http...) call, function based approach or interface based approach?

I don't understand when to use function way and when to use interface way. Which one is more idiomatic Golang way if I am writing my web server from scratch?

 

Use whatever fits your need. I doubt there is a generic

answer to this question. If it is clear, explicit, readable 

and understandable then it is "idiomatic" no matter what

technique/pattern you use.

Personally I dislike creating an interface just to allow testing

and prefer global functions: I'm thinking of the test as a

bit "secondary" and if the "real" code has only one

implementation of an interface this feels strange. An interface

signals: "Supply whatever implementation fits your need!"

But if there ever is just one "real" implementation this type

of announcement is not clear, explicit or especially

understandable. (Don't get me wrong, I think writing testable

code is important, but clear, understandable code is more

important.)

V.