add initial client tests (#25)

src/client.rs

@@ -187,6 +187,11 @@ pub struct Subscriber {
 
 impl Subscriber {
 
+    /// get the list of subscribed channels
+    pub fn get_subscribed(&self) -> &HashSet<String> {
+        &self.subscribed_channels
+    }
+
     /// await for next message published on the subscribed channels
     pub async fn next_message(&mut self) -> crate::Result<Message> {
         match self.receive_message().await {

src/server.rs

@@ -182,7 +182,7 @@ pub async fn run(listener: TcpListener, shutdown: impl Future) -> crate::Result<
     }
 
     // Extract the `shutdown_complete` receiver and transmitter
-    // ` explicitly drop shutdown_transmitter`. This is important, as the
+    // explicitly drop `shutdown_transmitter`. This is important, as the
     // `.await` below would otherwise never complete.
     let Listener { mut shutdown_complete_rx, shutdown_complete_tx, .. } = server;