option_inspect_none/
lib.rs

1pub trait OptionInspectNone<T> {
2    fn inspect_none(self, inspector_function: impl FnOnce()) -> Self;
3}
4
5impl<T> OptionInspectNone<T> for Option<T> {
6    fn inspect_none(self, inspector_function: impl FnOnce()) -> Self {
7        match &self {
8            Some(_) => (),
9            None => inspector_function(),
10        }
11        self
12    }
13}
14
15impl<T> OptionInspectNone<T> for &Option<T> {
16    fn inspect_none(self, inspector_function: impl FnOnce()) -> Self {
17        match &self {
18            Some(_) => (),
19            None => inspector_function(),
20        }
21        self
22    }
23}
24
25#[cfg(test)]
26mod tests {
27    use crate::OptionInspectNone;
28
29    #[test]
30    fn inspect_none_on_some() {
31        let mut inspector_function_called = false;
32        Some(()).inspect_none(|| inspector_function_called = true);
33        assert!(!inspector_function_called);
34    }
35
36    #[test]
37    fn inspect_none_on_none() {
38        let mut inspector_function_called = false;
39        None::<()>.inspect_none(|| inspector_function_called = true);
40        assert!(inspector_function_called);
41    }
42}
option_inspect_none/lib.rs

option_inspect_none/
lib.rs
