fake-socket 0.2.0

A simple fake socket for testing purpose.
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

use pin_project::pin_project;
use std::{
    marker::PhantomData,
    pin::Pin,
    task::{Context, Poll},
};

use futures::{Sink, Stream};
use tokio::sync::mpsc;

#[pin_project]
pub struct ReceiverStream<T, E> {
    #[pin]
    inner: mpsc::UnboundedReceiver<T>,
    _error: PhantomData<E>,
}

pub struct SenderSink<T, E> {
    inner: mpsc::UnboundedSender<T>,
    _error: PhantomData<E>,
}

#[pin_project]
pub struct FakeSocket<T, E> {
    #[pin]
    sender: SenderSink<T, E>,
    #[pin]
    receiver: ReceiverStream<T, E>,
}

pub struct FakeClient<T> {
    sender: mpsc::UnboundedSender<T>,
    receiver: mpsc::UnboundedReceiver<T>,
}

impl<T, E> ReceiverStream<T, E> {
    pub fn new(inner: mpsc::UnboundedReceiver<T>) -> Self {
        Self {
            inner,
            _error: PhantomData::default(),
        }
    }
}

impl<T, E> SenderSink<T, E> {
    pub fn new(inner: mpsc::UnboundedSender<T>) -> Self {
        Self {
            inner,
            _error: PhantomData::default(),
        }
    }
}

impl<T, E> FakeSocket<T, E> {
    pub fn new(rx: mpsc::UnboundedReceiver<T>, tx: mpsc::UnboundedSender<T>) -> Self {
        Self {
            sender: SenderSink::new(tx),
            receiver: ReceiverStream::new(rx),
        }
    }
}

impl<T, E> Stream for ReceiverStream<T, E> {
    type Item = Result<T, E>;

    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
        let data = futures::ready!(self.inner.poll_recv(cx));
        Poll::Ready(Ok(data).transpose())
    }
}

impl<T, E> Stream for FakeSocket<T, E> {
    type Item = Result<T, E>;

    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
        self.project().receiver.poll_next(cx)
    }
}

impl<T, E> Sink<T> for SenderSink<T, E> {
    type Error = E;

    fn poll_ready(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
        Poll::Ready(Ok(()))
    }

    fn start_send(self: Pin<&mut Self>, item: T) -> Result<(), Self::Error> {
        let _ = self.inner.send(item);
        Ok(())
    }

    fn poll_flush(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
        Poll::Ready(Ok(()))
    }

    fn poll_close(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
        Poll::Ready(Ok(()))
    }
}

impl<T, E> Sink<T> for FakeSocket<T, E> {
    type Error = E;

    fn poll_ready(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
        self.project().sender.poll_ready(cx)
    }

    fn start_send(self: Pin<&mut Self>, item: T) -> Result<(), Self::Error> {
        self.project().sender.start_send(item)
    }

    fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
        self.project().sender.poll_flush(cx)
    }

    fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
        self.project().sender.poll_close(cx)
    }
}

impl<T> FakeClient<T> {
    pub fn new(sender: mpsc::UnboundedSender<T>, receiver: mpsc::UnboundedReceiver<T>) -> Self {
        Self { sender, receiver }
    }

    pub fn send(&self, msg: T) -> Result<(), mpsc::error::SendError<T>> {
        self.sender.send(msg)
    }

    pub async fn recv(&mut self) -> Option<T> {
        self.receiver.recv().await
    }
}

/// Create fake client and fake socket. The socket could be sent to the function to be tested.
/// For example:
/// ```
/// let (mut client, socket) = create_fake_connect();
/// tokio::spawn(async move {
///     handle_socket(socket, state).await;
/// });
///
/// let msg = ...;
/// client.send(msg).await;
/// if let Some(msg1) = client.recv().await {
///    assert_eq!(msg1, ...);
/// }
/// ```
pub fn create_fake_connection<T, E>() -> (FakeClient<T>, FakeSocket<T, E>) {
    let (tx1, rx1) = mpsc::unbounded_channel();
    let (tx2, rx2) = mpsc::unbounded_channel();
    let socket = FakeSocket::<T, E>::new(rx1, tx2);
    let client = FakeClient::new(tx1, rx2);
    (client, socket)
}