12 releases (4 breaking)
new 0.4.0 | Oct 7, 2024 |
---|---|
0.3.1 | Oct 5, 2024 |
0.2.1 | Oct 2, 2024 |
0.1.1 | Sep 30, 2024 |
0.0.4 | Oct 16, 2022 |
#108 in Testing
1,373 downloads per month
Used in 2 crates
41KB
463 lines
socket-server-mocker
Mock socket server in Rust, for testing various network clients.
I was developing an application that needed to connect to an external server, and I was looking for a way to test the messages sent by the application to the server, directly with cargo test
. So I looked for a way to directly mock a network server in Rust, without having to integrate a real server in docker each time the tests were launched.
With this crate, it is possible to directly test the messages sent by your application which normally connects to a server.
Usage
Add the socket-server-mocker dependency to your Cargo.toml
for testing compilation:
[dev-dependencies]
socket-server-mocker = "0.4"
Example
You can view all example test codes in tests directory. In particular, you there are examples of mocking the protocols PostgreSQL, HTTP, DNS and SMTP.
Here is a simple example in TCP:
use socket_server_mocker::ServerMocker;
use socket_server_mocker::Instruction::*;
use socket_server_mocker::TcpServerMocker;
use std::io::{Read, Write};
use std::net::TcpStream;
use std::str::from_utf8;
// Mock a TCP server listening on port 35642. Note that the mock will only listen on the local interface.
let server = TcpServerMocker::new_with_port(35642).unwrap();
// Create the TCP client to test
let mut client = TcpStream::connect(server.socket_address()).unwrap();
// Mocked server behavior
server.add_mock_instructions(vec![
ReceiveMessageWithMaxSize(16), // The mocked server will first wait for the client to send a message
SendMessage(b"hello from server".to_vec()), // Then it will send a message to the client
]);
// TCP client sends its first message
client.write_all(b"hello from client").unwrap();
// Read a message sent by the mocked server
let mut buffer = [0; 1024];
let received_size = client.read(&mut buffer).unwrap();
// convert shrunk buffer to string
let received_message = from_utf8(&buffer[..received_size]).unwrap();
// Check that the message received by the client is the one sent by the mocked server
assert_eq!("hello from server", received_message);
// Check that the mocked server received the message sent by the client
assert_eq!(
"hello from clien", // Max 16 bytes, the word "client" is truncated
from_utf8(server.pop_received_message().unwrap().as_ref()).unwrap()
);
// New instructions for the mocked server
server.add_mock_instructions(vec![
ReceiveMessage, // Wait for another message from the tested client
SendMessageDependingOnLastReceivedMessage(|_| {
None
}), // No message is sent to the server
SendMessageDependingOnLastReceivedMessage(|last_received_message| {
// "hello2 from client"
let mut received_message_string: String = from_utf8(&last_received_message.unwrap()).unwrap().to_string();
// "hello2"
received_message_string.truncate(5);
Some(format!("{}2 from server", received_message_string).as_bytes().to_vec())
}), // Send a message to the client depending on the last received message by the mocked server
StopExchange, // Finally close the connection
]);
// Tested client send a message to the mocked server
client.write_all(b"hello2 from client").unwrap();
// Read a message sent by the mocked server
let mut buffer = [0; 1024];
let received_size = client.read(&mut buffer).unwrap();
// convert shrunk buffer to string
let received_message = from_utf8(&buffer[..received_size]).unwrap();
assert_eq!("hello2 from server", received_message);
assert_eq!(
"hello2 from client",
from_utf8(&*server.pop_received_message().unwrap()).unwrap()
);
// Check that no error has been raised by the mocked server
assert!(server.pop_server_error().is_none());
Another example in UDP:
use socket_server_mocker::{ServerMocker, UdpServerMocker};
use socket_server_mocker::Instruction::{SendMessage, SendMessageDependingOnLastReceivedMessage, ReceiveMessageWithMaxSize};
use std::net::UdpSocket;
use std::str::from_utf8;
// Mock a UDP server listening on port 35642. Note that the mock will only listen on the local interface.
let server = UdpServerMocker::new_with_port(35642).unwrap();
// Create the UDP client to test at a random port
let client_socket = UdpSocket::bind("127.0.0.1:0").unwrap();
client_socket.connect(server.socket_address()).unwrap();
// Mocked server behavior
server.add_mock_instructions(vec![
// The mocked server will first wait for the client to send a message, with max size = 32 bytes
ReceiveMessageWithMaxSize(32),
// Then it will send a message to the client
SendMessage(b"hello from server".to_vec()),
// Send nothing
SendMessageDependingOnLastReceivedMessage(|_| {
None
}),
// Send a message to the client depending on the last received message by the mocked server
SendMessageDependingOnLastReceivedMessage(|last_received_message| {
// "hello2 from client"
let mut received_message_string: String = from_utf8(&last_received_message.unwrap()).unwrap().to_string();
// "hello2"
received_message_string.truncate(5);
Some(format!("{}2 from server", received_message_string).as_bytes().to_vec())
}),
]
);
// UDP client sends its first message
client_socket.send(b"hello from client").unwrap();
// Read a message sent by the mocked server
let mut buffer = [0; 32];
let received_size = client_socket.recv(&mut buffer).unwrap();
// convert shrunk buffer to string
let received_message = from_utf8(&buffer[..received_size]).unwrap();
// Check that the message received by the client is the one sent by the mocked server
assert_eq!("hello from server", received_message);
// Check that the mocked server received the message sent by the client
assert_eq!(
"hello from client",
from_utf8(&*server.pop_received_message().unwrap()).unwrap()
);
let received_size = client_socket.recv(&mut buffer).unwrap();
// convert shrunk buffer to string
let received_message = from_utf8(&buffer[..received_size]).unwrap();
// Check that the message received by the client is the one sent by the mocked server
assert_eq!("hello2 from server", received_message);
// Check that no error has been raised by the mocked server
assert!(server.pop_server_error().is_none());
Development
- This project is easier to develop with just, a modern alternative to
make
. Install it withcargo install just
. - To get a list of available commands, run
just
. - To run tests, use
just test
.
Dependencies
~310–780KB
~18K SLoC