add old version test

Author: g-may

test/unit/test.natural_language_understanding.v1.js

@@ -37,10 +37,22 @@ describe('natural_language_understanding', function() {
     });
     done();
   });
+  
+  it('2016_01_23 version should work', function(done) {
+    nock(watson.NaturalLanguageUnderstandingV1.URL)
+      .post('/v1/analyze?version=' + watson.NaturalLanguageUnderstandingV1.VERSION_DATE_2016_01_23)
+      .reply(200, {});
+
+    const options = {
+      features: { concepts: {}, keywords: {} },
+      text: 'hello, this is a test'
+    };
+
+    nlu.analyze(options, done);
+  });
 
-  it('2017_02_27 version should work', function(done) {
+  it('analyze()', function(done) {
     nock(watson.NaturalLanguageUnderstandingV1.URL)
-      .persist()
       .post('/v1/analyze?version=' + watson.NaturalLanguageUnderstandingV1.VERSION_DATE_2017_02_27)
       .reply(200, {});
 
@@ -54,7 +66,6 @@ describe('natural_language_understanding', function() {
 
   it('should list models', function(done) {
     nock(watson.NaturalLanguageUnderstandingV1.URL)
-      .persist()
       .get('/v1/models?version=' + watson.NaturalLanguageUnderstandingV1.VERSION_DATE_2017_02_27)
       .reply(200, {});