Fix IPC unit test (#511)

* Fix IPC unit test

* updates

src/nni_manager/common/errors.ts

@@ -26,12 +26,14 @@ export namespace NNIErrorNames {
 }
 
 export class NNIError extends Error {
+    public cause!: Error | undefined;
     constructor (name: string, message: string, err?: Error) {
         super(message);
         this.name = name;
         if (err !== undefined) {
             this.stack = err.stack;
         }
+        this.cause = err;
     }
 }
 

src/nni_manager/core/ipcInterface.ts

@@ -103,7 +103,7 @@ class IpcInterface {
         try {
             const data: Buffer = encodeCommand(commandType, content);
             if (!this.outgoingStream.write(data)) {
-                this.logger.error('Commands jammed in buffer!');
+                this.logger.warning('Commands jammed in buffer!');
             }
         } catch (err) {
             throw new NNIError('Dispatcher Error', `Dispatcher Error: ${err.message}`, err);

src/nni_manager/core/test/ipcInterface.test.ts

@@ -25,6 +25,7 @@ import { Deferred } from 'ts-deferred';
 import { cleanupUnitTest, prepareUnitTest } from '../../common/utils';
 import * as CommandType from '../commands';
 import { createDispatcherInterface, IpcInterface } from '../ipcInterface';
+import { NNIError } from '../../common/errors';
 
 let sentCommands: {[key: string]: string}[] = [];
 const receivedCommands: {[key: string]: string}[] = [];
@@ -105,8 +106,13 @@ describe('core/protocol', (): void => {
     });
 
     it('sendCommand() should throw on too long command', (): void => {
-        assert.equal((<Error>commandTooLong).name, 'RangeError');
-        assert.equal((<Error>commandTooLong).message, 'Command too long');
+        if (commandTooLong === undefined) {
+            assert.fail('Should throw error')
+        } else {
+            const err: Error | undefined =  (<NNIError>commandTooLong).cause;
+            assert(err && err.name === 'RangeError');
+            assert(err && err.message === 'Command too long');
+        }
     });
 
     it('sendCommand() should throw on wrong command type', (): void => {