Propagate errors when testing

Testing with Mocha requires errors raised within flows to propagate
to the test runner, not getting swallowed by Node.

This commit tests whether Mocha's global functions exist and,
if they do, propagates exceptions that are raised there.

package.json

@@ -41,6 +41,7 @@
         "cors": "2.8.5",
         "cronosjs": "1.7.1",
         "denque": "2.1.0",
+        "detect-mocha": "^0.1.0",
         "express": "4.21.1",
         "express-session": "1.18.1",
         "form-data": "4.0.0",

packages/node_modules/@node-red/runtime/lib/flows/Flow.js

@@ -21,6 +21,7 @@ const flowUtil = require("./util");
 const context = require('../nodes/context');
 const hooks = require("@node-red/util").hooks;
 const credentials = require("../nodes/credentials");
+const detectMocha = require("detect-mocha");
 
 let Subflow;
 let Log;
@@ -804,6 +805,9 @@ function deliverMessageToDestination(sendEvent) {
         } catch(err) {
             Log.error(`Error delivering message to node:${sendEvent.destination.node._path} [${sendEvent.destination.node.type}]`)
             Log.error(err.stack)
+            if (detectMocha()) {
+                throw err;
+            }
         }
     }
 }

packages/node_modules/@node-red/runtime/lib/nodes/Node.js

@@ -21,6 +21,7 @@ var redUtil = require("@node-red/util").util;
 var Log = require("@node-red/util").log;
 var context = require("./context");
 var flows = require("../flows");
+var detectMocha = require("detect-mocha");
 const hooks = require("@node-red/util").hooks;
 
 
@@ -218,6 +219,9 @@ Node.prototype._emitInput = function(arg) {
                     );
                 } catch(err) {
                     node.error(err,arg);
+                    if (detectMocha()) {
+                        throw err;
+                    }
                 }
             } else if (node._inputCallbacks) {
                 // Multiple callbacks registered. Call each one, tracking eventual completion