main_test.go

package main

import (
	"testing"
	"time"

	"golang.org/x/net/context"

	"github.com/stretchr/testify/assert"
)

func TestContext(t *testing.T) {
	assert := assert.New(t)

	ctx := context.Background()
	contextWithCancel, cancel := context.WithCancel(ctx)

	cancel()

	select {
	case <-ctx.Done():
		println("parent")
		assert.True(true)
	case <-contextWithCancel.Done():
		println("child")
		assert.True(true)
	case <-time.After(time.Second):
		t.Error("timeout")
		t.Fail()
	}
}