it('treats options string as a secret', function () {
   const rawRes = {};
   const res = new SyntheticResponse(rawRes, {});
   res.cookie('hello', 'banana', 'potato');
   expect(rawRes.cookies).to.eql([
     {name: 'hello', value: 'banana'},
     {name: 'hello.sig', value: crypto.hmac('potato', 'banana')}
   ]);
 });
 it('supports signed cookies when a secret is provided', function () {
   const rawRes = {};
   const res = new SyntheticResponse(rawRes, {});
   res.cookie('hello', 'banana', {secret: 'potato'});
   expect(rawRes.cookies).to.eql([
     {name: 'hello', value: 'banana'},
     {name: 'hello.sig', value: crypto.hmac('potato', 'banana')}
   ]);
 });
 it('supports signed cookies with different algorithms', function () {
   const rawRes = {};
   const res = new SyntheticResponse(rawRes, {});
   res.cookie('hello', 'banana', {
     secret: 'potato',
     algorithm: 'sha512'
   });
   expect(rawRes.cookies).to.eql([
     {name: 'hello', value: 'banana'},
     {name: 'hello.sig', value: crypto.hmac('potato', 'banana', 'sha512')}
   ]);
 });