shimforge 0.1.3

Test Rust code without test-only traits or changes to production code.
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

//! Mocks bind to one instantiation of a generic function.

#![forbid(unsafe_code)]

use shimforge::{Session, mock};
use std::fmt::Display;
use std::io;
use std::path::Path;

fn archive<P: AsRef<Path>>(_target: P) -> io::Result<()> {
    Err(io::Error::new(
        io::ErrorKind::ReadOnlyFilesystem,
        "archive is sealed",
    ))
}

fn summarize<A: Display, B: Display, C: Display>(_head: A, _flag: B, _count: C) -> String {
    String::from("live summary")
}

fn is_stale<A, B, C>(_head: A, _flag: B, _count: C) -> bool {
    false
}

fn joined<S: AsRef<str>>(_separator: &str, _parts: &[S]) -> String {
    String::from("live join")
}

struct Queue {
    name: String,
}

impl Queue {
    fn publish<T: Display>(&self, payload: T) -> String {
        format!("{} <- {payload}", self.name)
    }
}

fn stale_with_borrowed_count<'a>(count: &'a str) -> bool {
    is_stale::<u16, bool, &'a str>(7, false, count)
}

#[test]
fn one_instantiation_is_mocked_and_restored_with_the_session() {
    let target = Path::new("virtual/ledger.tar");
    assert!(archive(target).is_err());
    {
        let mut session = Session::new();
        let archives = mock!(session, archive::<&Path>, fn(&Path) -> io::Result<()>);
        archives
            .expect()
            .with(|path| **path == *Path::new("virtual/ledger.tar"))
            .once()
            .returning(|_| Ok(()));
        assert!(archive(target).is_ok());
        session.verify();
    }
    assert_eq!(
        archive(target).unwrap_err().kind(),
        io::ErrorKind::ReadOnlyFilesystem
    );
}

#[test]
fn other_instantiations_keep_the_original_body() {
    let mut session = Session::new();
    let summaries = mock!(
        session,
        summarize::<&str, bool, i32>,
        fn(&str, bool, i32) -> String
    );
    let expected = summaries
        .expect()
        .with(|head, flag, count| **head == *"orders" && *flag && *count == 19)
        .once()
        .returns(String::from("mocked summary"));

    assert_eq!(summarize("orders", true, 19), "mocked summary");
    // A different set of type arguments compiles to a different function.
    assert_eq!(summarize(1u8, 2u8, 3u8), "live summary");
    assert_eq!(expected.calls(), 1);
}

#[test]
fn a_type_parameter_inside_a_slice_can_be_named_with_a_turbofish() {
    let mut session = Session::new();
    let joins = mock!(session, joined::<&str>, fn(&str, &[&str]) -> String);
    joins
        .expect()
        .with(|separator, parts| **separator == *" / " && parts.len() == 2)
        .once()
        .returning(|separator, parts| parts.join(separator));

    assert_eq!(joined(" / ", &["north", "south"]), "north / south");
    session.verify();
}

#[test]
fn a_caller_that_names_its_own_lifetime_reaches_the_same_instantiation() {
    let mut session = Session::new();
    let checks = mock!(
        session,
        is_stale::<u16, bool, &str>,
        fn(u16, bool, &str) -> bool
    );
    checks.expect().times(2).returns(true);

    assert!(is_stale(7u16, false, "12"));
    let count = String::from("12");
    assert!(stale_with_borrowed_count(&count));
    session.verify();
}

#[test]
fn generic_methods_are_mocked_per_type_argument() {
    let queue = Queue {
        name: String::from("reports"),
    };
    let mut session = Session::new();
    let publishes = mock!(session, Queue::publish::<u32>, fn(&Queue, u32) -> String);
    publishes
        .expect()
        .with(|queue, payload| queue.name == "reports" && *payload == 5)
        .once()
        .returning(|queue, payload| format!("{} dropped {payload}", queue.name));

    assert_eq!(queue.publish(5u32), "reports dropped 5");
    assert_eq!(queue.publish("5"), "reports <- 5");
    session.verify();
}