do not set content-language header when sending JSON to Personality Insights service

Fixes watson-developer-cloud#220

Author: nfriedly

services/personality_insights/v2.js

@@ -66,18 +66,26 @@ PersonalityInsights.prototype.profile = function(params, callback) { // eslint-d
   else
     content_type = 'application/json';
 
+  var headers = {
+    'Content-type'    : content_type,
+    'Accept-language' : params.accept_language || params.acceptLanguage || 'en'
+  };
+
+  // service bug: language in header overrides language in each JSON content item, so we can't set it on those requests
+  // (also, content-language doesn't really make sense on JSON)
+  if (params.language || params.text) {
+    headers['Content-language'] = params.language || 'en'
+  }
+
+
   var parameters = {
     options: {
       method: 'POST',
       url: '/v2/profile',
       body: params.text || pick(params, ['contentItems']),
       json: true,
       qs: pick(params, ['include_raw']),
-      headers: {
-        'Content-type'    : content_type,
-        'Content-language': params.language ? params.language : 'en',
-        'Accept-language' : params.accept_language || params.acceptLanguage || 'en'
-      }
+      headers: headers
     },
     defaultOptions: this._options
   };

test/test.personality_insights.v2.js

@@ -79,6 +79,7 @@ describe('personality_insights', function() {
       assert.equal(req.uri.href, service.url + service_path);
       assert.equal(body, JSON.stringify(payload));
       assert.equal(req.method, 'POST');
+      assert.equal(req.headers['Content-language'], undefined); // service bug: content-language header overrides the language specified in JSON for each content item, so it must not be set
       assert.equal(req.headers['Content-type'], 'application/json');
   });
 
@@ -89,6 +90,7 @@ describe('personality_insights', function() {
       assert.equal(req.uri.href, service.url + service_path);
       assert.equal(body, JSON.stringify(payload));
       assert.equal(req.method, 'POST');
+      assert.equal(req.headers['Content-language'], undefined); // service bug: content-language header overrides the language specified in JSON for each content item, so it must not be set
       assert.equal(req.headers['Content-type'], 'application/json');
   });