fix request with content-length > 0 and content-encoding: gzip (#371)

* test that head method works correctly

* uppercase methods sent to Request instance\n fixes head with content-length > 0 amongst other things

lib/test.js

@@ -26,7 +26,7 @@ module.exports = Test;
  */
 
 function Test(app, method, path) {
-  Request.call(this, method, path);
+  Request.call(this, method.toUpperCase(), path);
   this.redirects(0);
   this.buffer();
   this.app = app;

test/supertest.js

@@ -866,6 +866,26 @@ describe('.<http verb> works as expected', function() {
         .put('/')
         .expect(200, done);
   });
+  it('.head should work', function (done) {
+    var app = express();
+    app.head('/', function(req, res) {
+      res.statusCode = 200;
+      res.set('Content-Encoding', 'gzip');
+      res.set('Content-Length', '1024');
+      res.status(200);
+      res.end();
+    });
+
+    request(app)
+        .head('/')
+        .set('accept-encoding', 'gzip, deflate')
+        .end(function (err, res) {
+          if (err) return done(err);
+          res.should.have.property('statusCode', 200);
+          res.headers.should.have.property('content-length', '1024');
+          done();
+        });
+  });
 });
 
 describe('assert ordering by call order', function() {