fix cookies' secure detect

lib/application.js

@@ -145,7 +145,10 @@ module.exports = class Application extends Emitter {
     response.request = request;
     context.onerror = context.onerror.bind(context);
     context.originalUrl = request.originalUrl = req.url;
-    context.cookies = new Cookies(req, res, this.keys);
+    context.cookies = new Cookies(req, res, {
+      keys: this.keys,
+      secure: request.secure
+    });
     context.accept = request.accept = accepts(req);
     context.state = {};
     return context;

test/context/cookies.js

@@ -74,4 +74,37 @@ describe('ctx.cookies.set()', () => {
         });
     });
   });
+
+  describe('with secure', () => {
+    it('should get secure from request', done => {
+      const app = new Koa();
+
+      app.proxy = true;
+      app.keys = ['a', 'b'];
+
+      app.use(ctx => {
+        ctx.cookies.set('name', 'jon', { signed: true });
+        ctx.status = 204;
+      });
+
+      const server = app.listen();
+
+      request(server)
+      .get('/')
+      .set('x-forwarded-proto', 'https') // mock secure
+      .expect(204)
+      .end((err, res) => {
+        if (err) return done(err);
+
+        const cookies = res.headers['set-cookie'];
+        cookies.some(cookie => /^name=/.test(cookie)).should.be.ok;
+
+        cookies.some(cookie => /^name\.sig=/.test(cookie)).should.be.ok;
+
+        cookies.every(cookie => /secure/.test(cookie)).should.be.ok;
+
+        done();
+      });
+    });
+  });
 });

test/helpers/context.js

@@ -8,6 +8,8 @@ module.exports = (req, res) => {
   const socket = new Stream.Duplex();
   req = req || { headers: {}, socket: socket, __proto__: Stream.Readable.prototype };
   res = res || { _headers: {}, socket: socket, __proto__: Stream.Writable.prototype };
+  req.socket = req.socket || socket;
+  res.socket = res.socket || socket;
   res.getHeader = k => res._headers[k.toLowerCase()];
   res.setHeader = (k, v) => res._headers[k.toLowerCase()] = v;
   res.removeHeader = (k, v) => delete res._headers[k.toLowerCase()];