clients 0.1.0

Concrete-struct dependency injection for Rust using function pointers instead of trait objects
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

use clients::{Clock, Env, Filesystem, Random, get};
use std::future::Future;
use std::path::PathBuf;
use std::pin::Pin;
use std::task::{Context, Poll, RawWaker, RawWakerVTable, Waker};
use std::time::{Duration, SystemTime};

#[cfg(feature = "reqwest")]
use clients::http_client;
#[cfg(feature = "reqwest")]
use clients::test_deps;

fn block_on<F>(future: F) -> F::Output
where
    F: Future,
{
    let mut future = Box::pin(future);
    let waker = noop_waker();
    let mut context = Context::from_waker(&waker);

    loop {
        match Pin::as_mut(&mut future).poll(&mut context) {
            Poll::Ready(value) => return value,
            Poll::Pending => std::thread::yield_now(),
        }
    }
}

fn noop_waker() -> Waker {
    unsafe fn clone(_: *const ()) -> RawWaker {
        RawWaker::new(std::ptr::null(), &VTABLE)
    }

    unsafe fn wake(_: *const ()) {}
    unsafe fn wake_by_ref(_: *const ()) {}
    unsafe fn drop(_: *const ()) {}

    static VTABLE: RawWakerVTable = RawWakerVTable::new(clone, wake, wake_by_ref, drop);

    unsafe { Waker::from_raw(RawWaker::new(std::ptr::null(), &VTABLE)) }
}

#[test]
fn clock_exposes_now_and_sleep() {
    let _ = get::<Clock>().now();
    block_on(get::<Clock>().sleep(Duration::ZERO));
}

#[test]
fn env_exposes_process_information() {
    let env = get::<Env>();

    assert_eq!(
        env.current_dir().expect("current dir should resolve"),
        std::env::current_dir().expect("std current dir should resolve")
    );
    assert!(env.temp_dir().is_absolute());
    assert_eq!(env.var("__DEP_BUILTINS_SHOULD_NOT_EXIST__".into()), None);
}

#[test]
fn random_generates_bytes_and_integers() {
    let random = get::<Random>();

    let _ = random.next_u64();
    assert_eq!(random.fill_bytes(16).len(), 16);
}

#[test]
fn filesystem_reads_and_writes_bytes_and_strings() {
    let filesystem = get::<Filesystem>();
    let path = unique_temp_path("filesystem");

    filesystem
        .write_string(path.clone(), "hello".to_string())
        .expect("string write should succeed");
    assert_eq!(
        filesystem
            .read_string(path.clone())
            .expect("string read should succeed"),
        "hello"
    );

    filesystem
        .write(path.clone(), b"bytes".to_vec())
        .expect("binary write should succeed");
    assert_eq!(
        filesystem
            .read(path.clone())
            .expect("binary read should succeed"),
        b"bytes".to_vec()
    );

    std::fs::remove_file(path).expect("temp file should be removable");
}

#[cfg(feature = "uuid")]
#[test]
fn uuid_generates_uuid_strings() {
    let uuid = get::<clients::Uuid>().generate();
    assert_eq!(uuid.to_string().len(), 36);
}

#[cfg(feature = "reqwest")]
#[test]
fn http_client_can_be_overridden() {
    test_deps! {
        http_client.get => |_url| {
            Ok(clients::HttpResponse {
                status: 200,
                headers: Default::default(),
                body: b"ok".to_vec(),
            })
        },
    }

    let response = get::<clients::HttpClient>()
        .get("https://example.com".into())
        .expect("override should succeed");
    assert_eq!(response.status, 200);
    assert_eq!(response.body, b"ok".to_vec());
}

fn unique_temp_path(label: &str) -> PathBuf {
    let nanos = SystemTime::now()
        .duration_since(SystemTime::UNIX_EPOCH)
        .expect("system time should be after the unix epoch")
        .as_nanos();
    std::env::temp_dir().join(format!("clients-{label}-{nanos}.tmp"))
}