assertr/assertions/std/
mem.rs

1use crate::{AssertThat, Mode, Type, tracking::AssertionTracking};
2use core::fmt::Write;
3use indoc::writedoc;
4
5/// Static memory assertions for any type.
6#[allow(clippy::return_self_not_must_use)]
7pub trait MemAssertions {
8    fn needs_drop(self) -> Self;
9
10    fn need_drop(self) -> Self
11    where
12        Self: Sized,
13    {
14        self.needs_drop()
15    }
16}
17
18impl<T, M: Mode> MemAssertions for AssertThat<'_, Type<T>, M> {
19    #[track_caller]
20    fn needs_drop(self) -> Self {
21        self.track_assertion();
22        let actual = self.actual();
23        if !actual.needs_drop() {
24            self.fail(|w: &mut String| {
25                writedoc! {w, r"
26                    Type {actual:#?} was expected to need drop,
27
28                    but dropping it is guaranteed to have no side effect.
29
30                    You may forgot to `impl Drop` for this type.
31                ", actual = actual.get_type_name()}
32            });
33        }
34        self
35    }
36}
37
38#[cfg(test)]
39mod tests {
40    mod needs_drop {
41        use crate::assert_that_type;
42        use crate::prelude::*;
43        use indoc::formatdoc;
44
45        #[test]
46        fn succeeds_when_type_needs_drop() {
47            struct NeedsDrop;
48            impl Drop for NeedsDrop {
49                fn drop(&mut self) {
50                    // placeholder...
51                }
52            }
53
54            assert_that_type::<NeedsDrop>().needs_drop();
55        }
56
57        #[test]
58        fn panics_when_type_does_not_need_drop() {
59            struct DoeNotNeedDrop;
60
61            assert_that_panic_by(|| {
62                assert_that_type::<DoeNotNeedDrop>()
63                    .with_location(false)
64                    .needs_drop();
65            })
66            .has_type::<String>()
67            .is_equal_to(formatdoc! {r#"
68                    -------- assertr --------
69                    Type "assertr::assertions::std::mem::tests::needs_drop::panics_when_type_does_not_need_drop::DoeNotNeedDrop" was expected to need drop,
70
71                    but dropping it is guaranteed to have no side effect.
72
73                    You may forgot to `impl Drop` for this type.
74                    -------- assertr --------
75                "#});
76        }
77    }
78}
assertr/assertions/std/mem.rs

assertr/assertions/std/
mem.rs
