func expectCommon(p *gexpect.ExpectSubprocess, searchString string, timeout time.Duration) error {
var err error
p.Capture()
if timeout == 0 {
err = p.Expect(searchString)
} else {
err = p.ExpectTimeout(searchString, timeout)
}
if err != nil {
return fmt.Errorf(string(p.Collect()))
}
return nil
}