Fix for issue #214, request defaults not set when using Agent.

lib/request.js

@@ -339,7 +339,7 @@ methods.forEach(function(method){
       // https://tools.ietf.org/html/rfc6454#section-3
       req.withCredentials();
     }
-
+    this._setDefaults(req);
     return req;
   };
 });

test/request.js

@@ -175,6 +175,49 @@ describe('request', function () {
         .then(done, done);
     });
 
+    it('agent can be used to set default headers', function (done){
+      var agent = request.agent('https://httpbin.org');
+      agent.set("Header-Name", "header_value");
+
+      agent
+        .get('/headers')
+        .then(function (res){
+          res.should.have.status(200);
+          res.body.headers.should.have.property('Header-Name').that.equals("header_value");
+          agent.close();
+        })
+        .then(done, done);
+    });
+
+    it('agent can be used to set default bearer authentication', function (done){
+      var agent = request.agent('https://httpbin.org');
+      agent.set("Authorization", "Bearer test_bearer");
+
+      agent
+        .get('/bearer')
+        .then(function (res){
+          res.should.have.status(200);
+          res.should.be.json;
+          res.body.should.have.property('authenticated').that.equals(true);
+          res.body.should.have.property('token').that.equals("test_bearer");
+          agent.close();
+        })
+        .then(done, done);
+    });
+
+    it('agent can be used to set default basic authentication', function (done){
+      var agent = request.agent('https://httpbin.org');
+      agent.auth("user", "passwd");
+
+      agent
+        .get('/basic-auth/user/passwd')
+        .then(function (res){
+          res.should.have.status(200);
+          agent.close();
+        })
+        .then(done, done);
+    });
+
     it('automatically closes the server down once done with it', function (done) {
       var server = require('http').createServer(function (req, res) {
         res.writeHeader(200, { 'content-type' : 'text/plain' });