Golang: how to generate a net/http timeout Error to perform unit test

Question

I got a piece of code like below:

if timeoutErr, ok := err.(net.Error); ok && timeoutErr.Timeout() {
    // Some code that need to test
}

How could I generate a error that can match the condition here so the code will flow through the if.

Answer 1

Error is an interface:

type Error interface {
        error
        Timeout() bool   // Is the error a timeout?
        Temporary() bool // Is the error temporary?
}

To implement it, you'll need to do something like (untested):

type MyError struct {
  error
}

func (e MyError) Timeout() bool {
  return true
}

func (e MyError) Temporary() bool {
  return true
}

func (e MyError) Error() string {
  return ""
}

Note that you have to implement Error() too because Error embeds error .