failpoint not activated

[yechenyuyu]

I write this in foo.go:

func pingCapFail() (string, failpoint.Value) {
	failpoint.Inject("failpoint-name", func(val failpoint.Value) {
		failpoint.Return("unit-test", val)
	})
	return "success", nil
}

and i run failpoint-ctl enable , code becomes this;

func pingCapFail() (string, failpoint.Value) {
	if val, ok := failpoint.Eval(_curpkg_("failpoint-name")); ok {
		return "unit-test", val
	}
	return "success", nil
}

then in foo_test.go ,i write my test code like this:

func Test_pingCapFail(t *testing.T) {
	failpoint.Enable("failpoint-name", "return(5)")
	got, got1 := pingCapFail()
	if got != "unit-test" {
		t.Errorf("pingCapFail() got = %v, want %v", got, "unit-test")
	}
	if !reflect.DeepEqual(got1, 5) {
		t.Errorf("pingCapFail() got1 = %v, want %v", got1, 5)
	}
}

and it fails, and obviously the failpoint is not activated, can someone tell me why?