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testinggogoroutine

how to test the result in goroutine without wait in test


When I do ut of golang, I sometimes need to test the result in goroutine, I was using time.Sleep to test, I am wondering is there any better way to test.

let's say I have an example code like this

func Hello() {
    go func() {
        // do something and store the result for example in db
    }()
    // do something
}

Then when I test the func, I want to test both result in goroutine, I am doing this:

 func TestHello(t *testing.T) {
        Hello()
        time.Sleep(time.Second) // sleep for a while so that goroutine can finish
        // test the result of goroutine
 }

is there any better way to test this?

Basically, in real logic, I don't care the result in goroutine, I don't need to wait for it finished. but in test, I want to check after it finished.


Solution

  • If you really want to check the result of a goroutine, you should use a channel like so:

    package main
    
    import (
        "fmt"
    )
    
    func main() {
        // in test
        c := Hello()
        if <-c != "done" {
            fmt.Println("assert error")
        }
    
        // not want to check result
        Hello()
    }
    
    func Hello() <-chan string {
        c := make(chan string)
        go func() {
            fmt.Println("do something")
            c <- "done"
        }()
        return c
    }
    

    https://play.golang.org/p/zUpNXg61Wn