molc provides a mock (fake) language client for testing language servers.
You can see specific examples of molc use in ELS.
use lsp_types::{Url, Value};
use molc::{FakeClient, LangServer, RedirectableStdout};
use molc::oneline_range;
pub struct Server {
stdout_redirect: Option<std::sync::mpsc::Sender<Value>>,
...
}
impl LangServer for Server {
fn dispatch(&mut self, msg: impl Into<Value>) -> Result<(), Box<dyn std::error::Error>> {
self.dispatch(msg)
}
}
impl RedirectableStdout for Server {
fn sender(&self) -> Option<&std::sync::mpsc::Sender<Value>> {
self.stdout_redirect.as_ref()
}
}
impl Server {
fn bind_fake_client() -> FakeClient<Self> {
// The server should send responses to this channel at least during testing.
let (sender, receiver) = std::sync::mpsc::channel();
DummyClient::new(
Server::new(Some(sender)),
receiver,
)
}
fn init(&mut self, msg: &Value, id: i64) -> ELSResult<()> {
self.send_log("initializing the language server")?;
let result = InitializeResult {
...
};
self.init_services();
self.send_stdout(&json!({
"jsonrpc": "2.0",
"id": id,
"result": result,
}))
}
...
}
#[test]
fn test_references() -> Result<(), Box<dyn std::error::Error>> {
let mut client = Server::bind_fake_client();
client.request_initialize()?;
let uri = Url::from_file_path(Path::new(FILE_A).canonicalize()?).unwrap();
client.notify_open(FILE_A)?;
let locations = client.request_references(uri, 1, 4)?.unwrap();
assert_eq!(locations.len(), 1);
assert_eq!(&locations[0].range, &oneline_range(1, 4, 5));
Ok(())
}