assertables/assert_count/
assert_count_lt_x.rs

1//! Assert a count is less than an expression.
2//!
3//! Pseudocode:<br>
4//! a.count() < b
5//!
6//! # Example
7//!
8//! ```rust
9//! use assertables::*;
10//!
11//! let a = "x".chars();
12//! let b = 2;
13//! assert_count_lt_x!(a, b);
14//! ```
15//!
16//! # Module macros
17//!
18//! * [`assert_count_lt_x`](macro@crate::assert_count_lt_x)
19//! * [`assert_count_lt_x_as_result`](macro@crate::assert_count_lt_x_as_result)
20//! * [`debug_assert_count_lt_x`](macro@crate::debug_assert_count_lt_x)
21
22/// Assert a count is less than an expression.
23///
24/// Pseudocode:<br>
25/// a.count() < b
26///
27/// * If true, return Result `Ok((a.count(), b))`.
28///
29/// * Otherwise, return Result `Err(message)`.
30///
31/// This macro is useful for runtime checks, such as checking parameters,
32/// or sanitizing inputs, or handling different results in different ways.
33///
34/// # Module macros
35///
36/// * [`assert_count_lt_x`](macro@crate::assert_count_lt_x)
37/// * [`assert_count_lt_x_as_result`](macro@crate::assert_count_lt_x_as_result)
38/// * [`debug_assert_count_lt_x`](macro@crate::debug_assert_count_lt_x)
39///
40#[macro_export]
41macro_rules! assert_count_lt_x_as_result {
42    ($a:expr, $b:expr $(,)?) => {
43        match (&$a, &$b) {
44            (a, b) => {
45                let a_count = a.clone().count();
46                if a_count < *b {
47                    Ok((a_count, *b))
48                } else {
49                    Err(format!(
50                        concat!(
51                            "assertion failed: `assert_count_lt_x!(a, b)`\n",
52                            "https://docs.rs/assertables/",
53                            env!("CARGO_PKG_VERSION"),
54                            "/assertables/macro.assert_count_lt_x.html\n",
55                            " a label: `{}`,\n",
56                            " a debug: `{:?}`,\n",
57                            " a.count(): `{:?}`,\n",
58                            " b label: `{}`,\n",
59                            " b debug: `{:?}`"
60                        ),
61                        stringify!($a),
62                        a,
63                        a_count,
64                        stringify!($b),
65                        b
66                    ))
67                }
68            }
69        }
70    };
71}
72
73#[cfg(test)]
74mod test_assert_count_lt_x_as_result {
75    use std::sync::Once;
76
77    #[test]
78    fn lt() {
79        let a = "x".chars();
80        let b = 2;
81        for _ in 0..1 {
82            let actual = assert_count_lt_x_as_result!(a, b);
83            assert_eq!(actual.unwrap(), (1, 2));
84        }
85    }
86
87    #[test]
88    fn lt_once() {
89        static A: Once = Once::new();
90        fn a() -> std::str::Chars<'static> {
91            if A.is_completed() {
92                panic!("A.is_completed()")
93            } else {
94                A.call_once(|| {})
95            }
96            "x".chars()
97        }
98
99        static B: Once = Once::new();
100        fn b() -> usize {
101            if B.is_completed() {
102                panic!("B.is_completed()")
103            } else {
104                B.call_once(|| {})
105            }
106            2
107        }
108
109        assert_eq!(A.is_completed(), false);
110        assert_eq!(B.is_completed(), false);
111        let result = assert_count_lt_x_as_result!(a(), b());
112        assert!(result.is_ok());
113        assert_eq!(A.is_completed(), true);
114        assert_eq!(B.is_completed(), true);
115    }
116
117    #[test]
118    fn eq() {
119        let a = "x".chars();
120        let b = 1;
121        let actual = assert_count_lt_x_as_result!(a, b);
122        let message = concat!(
123            "assertion failed: `assert_count_lt_x!(a, b)`\n",
124            "https://docs.rs/assertables/",
125            env!("CARGO_PKG_VERSION"),
126            "/assertables/macro.assert_count_lt_x.html\n",
127            " a label: `a`,\n",
128            " a debug: `Chars(['x'])`,\n",
129            " a.count(): `1`,\n",
130            " b label: `b`,\n",
131            " b debug: `1`"
132        );
133        assert_eq!(actual.unwrap_err(), message);
134    }
135
136    #[test]
137    fn gt() {
138        let a = "xx".chars();
139        let b = 1;
140        let actual = assert_count_lt_x_as_result!(a, b);
141        let message = concat!(
142            "assertion failed: `assert_count_lt_x!(a, b)`\n",
143            "https://docs.rs/assertables/",
144            env!("CARGO_PKG_VERSION"),
145            "/assertables/macro.assert_count_lt_x.html\n",
146            " a label: `a`,\n",
147            " a debug: `Chars(['x', 'x'])`,\n",
148            " a.count(): `2`,\n",
149            " b label: `b`,\n",
150            " b debug: `1`"
151        );
152        assert_eq!(actual.unwrap_err(), message);
153    }
154}
155
156/// Assert a count is less than an expression.
157///
158/// Pseudocode:<br>
159/// a.count() < b
160///
161/// * If true, return `(a.count(), b)`.
162///
163/// * Otherwise, call [`panic!`] with a message and the values of the
164///   expressions with their debug representations.
165///
166/// # Examples
167///
168/// ```rust
169/// use assertables::*;
170/// # use std::panic;
171///
172/// # fn main() {
173/// let a = "x".chars();
174/// let b = 2;
175/// assert_count_lt_x!(a, b);
176///
177/// # let result = panic::catch_unwind(|| {
178/// // This will panic
179/// let a = "xx".chars();
180/// let b = 1;
181/// assert_count_lt_x!(a, b);
182/// # });
183/// // assertion failed: `assert_count_lt_x!(a, b)`
184/// // https://docs.rs/assertables/9.7.0/assertables/macro.assert_count_lt_x.html
185/// //  a label: `a`,
186/// //  a debug: `Chars(['x', 'x'])`,
187/// //  a.count(): `2`",
188/// //  b label: `b`,
189/// //  b debug: `1`
190/// # let actual = result.unwrap_err().downcast::<String>().unwrap().to_string();
191/// # let message = concat!(
192/// #     "assertion failed: `assert_count_lt_x!(a, b)`\n",
193/// #     "https://docs.rs/assertables/", env!("CARGO_PKG_VERSION"), "/assertables/macro.assert_count_lt_x.html\n",
194/// #     " a label: `a`,\n",
195/// #     " a debug: `Chars(['x', 'x'])`,\n",
196/// #     " a.count(): `2`,\n",
197/// #     " b label: `b`,\n",
198/// #     " b debug: `1`"
199/// # );
200/// # assert_eq!(actual, message);
201/// # }
202/// ```
203///
204/// # Module macros
205///
206/// * [`assert_count_lt_x`](macro@crate::assert_count_lt_x)
207/// * [`assert_count_lt_x_as_result`](macro@crate::assert_count_lt_x_as_result)
208/// * [`debug_assert_count_lt_x`](macro@crate::debug_assert_count_lt_x)
209///
210#[macro_export]
211macro_rules! assert_count_lt_x {
212    ($a:expr, $b:expr $(,)?) => {
213        match $crate::assert_count_lt_x_as_result!($a, $b) {
214            Ok(x) => x,
215            Err(err) => panic!("{}", err),
216        }
217    };
218    ($a:expr, $b:expr, $($message:tt)+) => {
219        match $crate::assert_count_lt_x_as_result!($a, $b) {
220            Ok(x) => x,
221            Err(err) => panic!("{}\n{}", format_args!($($message)+), err),
222        }
223    };
224}
225
226#[cfg(test)]
227mod test_assert_count_lt_x {
228    use std::panic;
229
230    #[test]
231    fn lt() {
232        let a = "x".chars();
233        let b = 2;
234        for _ in 0..1 {
235            let actual = assert_count_lt_x!(a, b);
236            assert_eq!(actual, (1, 2));
237        }
238    }
239
240    #[test]
241    fn eq() {
242        let result = panic::catch_unwind(|| {
243            let a = "x".chars();
244            let b = 1;
245            let _actual = assert_count_lt_x!(a, b);
246        });
247        let message = concat!(
248            "assertion failed: `assert_count_lt_x!(a, b)`\n",
249            "https://docs.rs/assertables/",
250            env!("CARGO_PKG_VERSION"),
251            "/assertables/macro.assert_count_lt_x.html\n",
252            " a label: `a`,\n",
253            " a debug: `Chars(['x'])`,\n",
254            " a.count(): `1`,\n",
255            " b label: `b`,\n",
256            " b debug: `1`"
257        );
258        assert_eq!(
259            result
260                .unwrap_err()
261                .downcast::<String>()
262                .unwrap()
263                .to_string(),
264            message
265        );
266    }
267
268    #[test]
269    fn gt() {
270        let result = panic::catch_unwind(|| {
271            let a = "xx".chars();
272            let b = 1;
273            let _actual = assert_count_lt_x!(a, b);
274        });
275        let message = concat!(
276            "assertion failed: `assert_count_lt_x!(a, b)`\n",
277            "https://docs.rs/assertables/",
278            env!("CARGO_PKG_VERSION"),
279            "/assertables/macro.assert_count_lt_x.html\n",
280            " a label: `a`,\n",
281            " a debug: `Chars(['x', 'x'])`,\n",
282            " a.count(): `2`,\n",
283            " b label: `b`,\n",
284            " b debug: `1`"
285        );
286        assert_eq!(
287            result
288                .unwrap_err()
289                .downcast::<String>()
290                .unwrap()
291                .to_string(),
292            message
293        );
294    }
295}
296
297/// Assert a count is less than an expression.
298///
299/// Pseudocode:<br>
300/// a.count() < b
301///
302/// This macro provides the same statements as [`assert_count_lt_x`](macro.assert_count_lt_x.html),
303/// except this macro's statements are only enabled in non-optimized
304/// builds by default. An optimized build will not execute this macro's
305/// statements unless `-C debug-assertions` is passed to the compiler.
306///
307/// This macro is useful for checks that are too expensive to be present
308/// in a release build but may be helpful during development.
309///
310/// The result of expanding this macro is always type checked.
311///
312/// An unchecked assertion allows a program in an inconsistent state to
313/// keep running, which might have unexpected consequences but does not
314/// introduce unsafety as long as this only happens in safe code. The
315/// performance cost of assertions, however, is not measurable in general.
316/// Replacing `assert*!` with `debug_assert*!` is thus only encouraged
317/// after thorough profiling, and more importantly, only in safe code!
318///
319/// This macro is intended to work in a similar way to
320/// [`::std::debug_assert`](https://doc.rust-lang.org/std/macro.debug_assert.html).
321///
322/// # Module macros
323///
324/// * [`assert_count_lt_x`](macro@crate::assert_count_lt_x)
325/// * [`assert_count_lt_x`](macro@crate::assert_count_lt_x)
326/// * [`debug_assert_count_lt_x`](macro@crate::debug_assert_count_lt_x)
327///
328#[macro_export]
329macro_rules! debug_assert_count_lt_x {
330    ($($arg:tt)*) => {
331        if $crate::cfg!(debug_assertions) {
332            $crate::assert_count_lt_x!($($arg)*);
333        }
334    };
335}
assertables/assert_count/assert_count_lt_x.rs

assertables/assert_count/
assert_count_lt_x.rs
