cln_plugin : Add basic test to cln_plugin

plugins/src/lib.rs

@@ -718,4 +718,68 @@ mod test {
         let builder = Builder::new(tokio::io::stdin(), tokio::io::stdout());
         let _ = builder.start(state);
     }
+
+    #[tokio::test]
+    async fn logs_become_json_rpc_notifications() {
+        // The input and output for testing the plugin behavior
+        let (input, input_writer) = tokio::net::UnixStream::pair().unwrap();
+        let (output, output_reader) = tokio::net::UnixStream::pair().unwrap();
+
+        let mut framed_reader = FramedRead::new(output_reader, JsonCodec::default());
+        let mut input_writer = FramedWrite::new(input_writer, JsonCodec::default());
+
+        // Send the get_manifest method
+        let get_manifest = serde_json::json!({
+            "jsonrpc" : "2.0",
+            "method" : "getmanifest",
+            "id" : 1,
+            "params" : {}
+        });
+        let init = serde_json::json!({
+            "jsonrpc" : "2.0",
+            "method" : "init",
+            "id" : 2,
+            "params" : {
+                "options" : {},
+                "configuration" : {
+                    "lightning-dir" : "/tmp/lightning-dir",
+                    "rpc-file" : "rpc",
+                    "startup" : true,
+                    "network" : "testnet",
+                    "feature_set" : {},
+                }
+            }
+        });
+        input_writer.send(get_manifest).await.unwrap();
+        input_writer.send(init).await.unwrap();
+
+        // We create a scope here
+        // At the bottom of this scope the configured_plugin
+        // should be dropped and all logs should be flushed
+        {
+            // Configure the plugin and the logger
+            let builder: Builder<(), _, _> = Builder::new(input, output);
+            let _ = builder.configure().await.unwrap().unwrap();
+
+            // builder.configure() configures our logger
+            // Every LogEntry should now be written to `output`-stream
+            // as a json-rpc notification.
+            log::info!("I'm a log message");
+        }
+
+        // Check the output_reader the find the log message
+        let duration = std::time::Duration::from_millis(10);
+        let mut found_message = false;
+        while let Ok(Some(msg)) = tokio::time::timeout(duration, framed_reader.next()).await {
+            if msg.is_ok() {
+                let msg = msg.unwrap();
+                if msg.get("method") == Some(&json!("log")) {
+                    if msg["params"]["message"] == json!("I'm a log message") {
+                        found_message = true
+                    }
+                }
+            }
+        }
+        assert!(found_message)
+    }
 }