assertr 0.5.3

Fluent assertions for the Rust programming language.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257

use crate::{AssertThat, Mode, tracking::AssertionTracking};
use core::fmt::Debug;
use tokio::sync::RwLock;

/// Assertions for tokio's [`RwLock`] type.
#[allow(clippy::return_self_not_must_use)]
#[cfg_attr(feature = "fluent", assertr_derive::fluent_aliases)]
pub trait TokioRwLockAssertions<T: Debug> {
    #[cfg_attr(feature = "fluent", fluent_alias("not_be_locked"))]
    fn is_not_locked(self) -> Self;

    fn is_free(self) -> Self
    where
        Self: Sized,
    {
        self.is_not_locked()
    }

    fn is_read_locked(self) -> Self;

    fn is_write_locked(self) -> Self;
}

impl<T: Debug, M: Mode> TokioRwLockAssertions<T> for AssertThat<'_, RwLock<T>, M> {
    #[track_caller]
    fn is_not_locked(self) -> Self
    where
        T: Debug,
    {
        self.track_assertion();
        if self.actual().try_write().is_err() {
            // Cannot be locked for writing, must already be read- or write-locked than!
            if self.actual().try_read().is_err() {
                // RwLock allows multiple readers, but we cannot read again, so existing lock must be write-lock!
                self.fail(format_args!(
                    "Actual: {actual:?}\n\nwas expected to not be read- or write-locked, but it is!\n\nIt is currently write-locked!\n",
                    actual = self.actual(),
                ));
            } else {
                self.fail(format_args!(
                    "Actual: {actual:?}\n\nwas expected to not be read- or write-locked, but it is!\n\nIt is currently read-locked!\n",
                    actual = self.actual(),
                ));
            }
        }
        self
    }

    #[track_caller]
    fn is_read_locked(self) -> Self
    where
        T: Debug,
    {
        self.track_assertion();
        if self.actual().try_write().is_ok() {
            // Can be locked for writing, must have zero locks than!
            self.fail(format_args!(
                "Actual: {actual:?}\n\nwas expected to be read-locked, but it is not!\n\nIt is not locked at all!\n",
                actual = self.actual(),
            ));
        } else {
            // Cannot be locked for writing, must already be read- or write-locked than!
            if self.actual().try_read().is_err() {
                // RwLock allows multiple readers, but we cannot read again, so existing lock must be write-lock!
                self.fail(format_args!(
                    "Actual: {actual:?}\n\nwas expected to be read-locked, but it is not!\n\nIt is currently write-locked!\n",
                    actual = self.actual(),
                ));
            }
        }
        self
    }

    #[track_caller]
    fn is_write_locked(self) -> Self
    where
        T: Debug,
    {
        self.track_assertion();
        if self.actual().try_write().is_ok() {
            // Can be locked for writing, must have zero locks than!
            self.fail(format_args!(
                "Actual: {actual:?}\n\nwas expected to be write-locked, but it is not!\n",
                actual = self.actual(),
            ));
        } else {
            // Cannot be locked for writing, must already be read- or write-locked than!
            if self.actual().try_read().is_ok() {
                // RwLock allows multiple readers, and we can read again, so existing lock must be read-lock!
                self.fail(format_args!(
                    "Actual: {actual:?}\n\nwas expected to be write-locked, but it is not!\n\nIt is currently read-locked!\n",
                    actual = self.actual(),
                ));
            }
        }
        self
    }
}

#[cfg(test)]
mod tests {
    mod is_not_locked {
        use crate::prelude::*;
        use indoc::formatdoc;
        use tokio::sync::RwLock;

        #[test]
        fn succeeds_when_not_locked() {
            let rw_lock = RwLock::new(42);
            assert_that!(rw_lock).is_not_locked();
        }

        #[tokio::test]
        async fn panics_when_write_locked() {
            let rw_lock = RwLock::new(42);
            let rw_lock_write_guard = rw_lock.write().await;

            assert_that_panic_by(|| assert_that!(&rw_lock).with_location(false).is_not_locked())
                .has_type::<String>()
                .is_equal_to(formatdoc! {r#"
                    -------- assertr --------
                    Actual: RwLock {{ data: <locked> }}

                    was expected to not be read- or write-locked, but it is!

                    It is currently write-locked!
                    -------- assertr --------
                "#});

            drop(rw_lock_write_guard);
        }

        #[tokio::test]
        async fn panics_when_read_locked() {
            let rw_lock = RwLock::new(42);
            let rw_lock_read_guard = rw_lock.read().await;

            assert_that_panic_by(|| assert_that!(&rw_lock).with_location(false).is_not_locked())
                .has_type::<String>()
                .is_equal_to(formatdoc! {r#"
                    -------- assertr --------
                    Actual: RwLock {{ data: 42 }}

                    was expected to not be read- or write-locked, but it is!

                    It is currently read-locked!
                    -------- assertr --------
                "#});

            drop(rw_lock_read_guard);
        }
    }

    mod is_read_locked {
        use crate::prelude::*;
        use indoc::formatdoc;
        use tokio::sync::RwLock;

        #[tokio::test]
        async fn succeeds_when_read_locked() {
            let rw_lock = RwLock::new(42);
            let rw_lock_read_guard = rw_lock.read().await;
            assert_that!(&rw_lock).is_read_locked();
            drop(rw_lock_read_guard);
        }

        #[tokio::test]
        async fn panics_when_write_locked() {
            let rw_lock = RwLock::new(42);
            let rw_lock_write_guard = rw_lock.write().await;

            assert_that_panic_by(|| assert_that!(&rw_lock).with_location(false).is_read_locked())
                .has_type::<String>()
                .is_equal_to(formatdoc! {r#"
                    -------- assertr --------
                    Actual: RwLock {{ data: <locked> }}

                    was expected to be read-locked, but it is not!

                    It is currently write-locked!
                    -------- assertr --------
                "#});

            drop(rw_lock_write_guard);
        }

        #[test]
        fn panics_when_not_locked_at_all() {
            let rw_lock = RwLock::new(42);

            assert_that_panic_by(|| assert_that!(rw_lock).with_location(false).is_read_locked())
                .has_type::<String>()
                .is_equal_to(formatdoc! {r#"
                    -------- assertr --------
                    Actual: RwLock {{ data: 42 }}

                    was expected to be read-locked, but it is not!

                    It is not locked at all!
                    -------- assertr --------
                "#});
        }
    }

    mod is_write_locked {
        use crate::prelude::*;
        use indoc::formatdoc;
        use tokio::sync::RwLock;

        #[tokio::test]
        async fn succeeds_when_write_locked() {
            let rw_lock = RwLock::new(42);
            let rw_lock_write_guard = rw_lock.write().await;
            assert_that!(&rw_lock).is_write_locked();
            drop(rw_lock_write_guard);
        }

        #[tokio::test]
        async fn panics_when_read_locked() {
            let rw_lock = RwLock::new(42);
            let rw_lock_read_guard = rw_lock.read().await;

            assert_that_panic_by(|| {
                assert_that!(&rw_lock)
                    .with_location(false)
                    .is_write_locked()
            })
            .has_type::<String>()
            .is_equal_to(formatdoc! {r#"
                    -------- assertr --------
                    Actual: RwLock {{ data: 42 }}

                    was expected to be write-locked, but it is not!

                    It is currently read-locked!
                    -------- assertr --------
                "#});

            drop(rw_lock_read_guard);
        }

        #[test]
        fn panics_when_not_write_locked() {
            let rw_lock = RwLock::new(42);

            assert_that_panic_by(|| assert_that!(rw_lock).with_location(false).is_write_locked())
                .has_type::<String>()
                .is_equal_to(formatdoc! {r#"
                    -------- assertr --------
                    Actual: RwLock {{ data: 42 }}

                    was expected to be write-locked, but it is not!
                    -------- assertr --------
                "#});
        }
    }
}