more comments to explain wtf is going on with echo test

tests/echo-server.js

@@ -1,7 +1,19 @@
+/*
+ * This NodeJS file starts a websocket echo server
+ * You don't need to manually invoke this
+ * Just run the tests by running client.marian/test.sh
+ * It will start this server and run pytests
+ *
+ * If this doesn't work, and you are debugging, first make sure you have
+ * nodejs version 10 or higher installed on your machine
+ */
+
 const WebSocket = require('ws');
 
 const wss = new WebSocket.Server({ port: 8080 });
 
+console.log("Echo websocket running at port 8080")
+
 function sleep(ms) {
     return new Promise(resolve => setTimeout(resolve, ms));
 }

tests/test_mc.py

@@ -1,3 +1,12 @@
+"""
+This test shouldn't be run directly with pytest
+(unless you really get what's going on)
+
+It is meant to be run by invoking client.marian/test.sh
+that shell script spins up a websocket echo server with artificial latency
+which this script talks to
+"""
+
 import pytest
 from essential_generators import DocumentGenerator