code: func Zerof(t TestingT, i interface{}, msg string, args ...interface{}) {
  	if h, ok := t.(tHelper); ok {
  		h.Helper()
  	}
  	if assert.Zerof(t, i, msg, args...) {
  		return
  	}
  	t.FailNow()
  }
docs: // Zerof asserts that i is the zero value for its type.