testing - 如何测试延迟的 Go 语句？

Question

如何测试 doStuff 函数？ ( Playground :http://play.golang.org/p/aPFSlaBLgX)

package myPackage

var locked = false

func doStuff() {
    defer unlock()
    lock()
    // some task that can cause errors
    // need to test if lock was really unlocked
    // this is just a simple example, things can go complex on real world
    panic("!")
}

func lock() {
    locked = true
}

func unlock() {
    locked = false
}

换句话说:如何测试使用defer 语句的代码？应使用哪些通用策略来测试延迟调用？如果没有通用的做法，如何测试这段具体的代码？

PS:Go playground 只允许 package main

Answer 1

长话短说

To test a panicked state the assertions should be deffered

看起来要测试 panic 状态，我们应该延迟测试断言:

package myPackage

import "testing"

func TestLock(t *testing.T) {
    defer func (){
        if locked == true {
            t.Error("Expected locked to be false but got locked =", locked)
        }
    }() // do assertions on panicked state ↑
    defer func (){ recover() }() // recover from panic ↑
    doStuff() // this will panic and code execution will flow up ↑
    // and, of course, execution will never reach below this line ---
    // don't put assertions here
}

发生这种情况是因为在 doStuff() 下没有执行任何代码，因为我们正在模拟 panic，因此应该推迟断言，以便它们处于“paniced scope” .