如何测试main（）函数中正在调用的特定方法

I want to test whether newrelic.NewConfig and newrelic.NewApplication are being called in the main() function.

import (
    "github.com/newrelic/go-agent"  
)

func main() {
    /* NewRelic configuration */
    newRelicConfig := newrelic.NewConfig("my-app-name", 
    os.Getenv("NEW_RELIC_LICENSE_KEY"))
    app, err := newrelic.NewApplication(newRelicConfig)

    // followed by other code
}

Should I move that code into a separate function within the main package, like:

func SetupNewRelicConfig() Application {
    newRelicConfig := newrelic.NewConfig("my-app-name", 
    os.Getenv("NEW_RELIC_LICENSE_KEY"))
    app, err := newrelic.NewApplication(newRelicConfig)

    if err != nil {
      log.Fatal(err)
    }

    return app
}

This way I can just check if the SetupNewRelicConfig is called or not.

What is the right way to test this?

Are you hoping to test this from an automated test, or as a runtime assertion of some type?

Assuming you're looking to add an automated test to your suite:

You need to find a way to mock the functions exported by the NewRelic package.

A very cheap way to do this is described here ("Monkey Patching in Golang"):

https://husobee.github.io/golang/testing/unit-test/2015/06/08/golang-unit-testing.html

A more comprehensive approach requires you to add these function calls to a struct that can be swapped by your test suite. See dependency injection, as described here:

https://medium.com/@zach_4342/dependency-injection-in-golang-e587c69478a8

Finally, look into using a mocking framework. I've had great luck with the mocking in stretchr's testify project.