Add tests.

test/http/request.test.js

@@ -668,6 +668,59 @@ describe('http.ServerRequest', function() {
       });
     });
 
+    describe('encountering an error saving existing session', function() {
+      var passport = new Passport();
+
+      var req = new Object();
+      req.logout = request.logout;
+      req.isAuthenticated = request.isAuthenticated;
+      req.isUnauthenticated = request.isUnauthenticated;
+      req.user = { id: '1', username: 'root' };
+      req._passport = {};
+      req._passport.instance = passport;
+      req._sessionManager = passport._sm;
+      req.session = { id: '1' };
+      req.session['passport'] = {};
+      req.session['passport'].user = '1';
+      req.session.save = function(cb) {
+        expect(req.session['passport'].user).to.be.undefined;
+        process.nextTick(function() {
+          cb(new Error('something went wrong'));
+        });
+      };
+      req.session.regenerate = function(cb) {
+        req.session = { id: '2' };
+        process.nextTick(cb);
+      };
+
+      var error;
+
+      before(function(done) {
+        req.logout(function(err) {
+          error = err;
+          done();
+        });
+      });
+
+      it('should error', function() {
+        expect(error).to.be.an.instanceOf(Error);
+        expect(error.message).to.equal('something went wrong');
+      });
+
+      it('should not be authenticated', function() {
+        expect(req.isAuthenticated()).to.be.false;
+        expect(req.isUnauthenticated()).to.be.true;
+      });
+
+      it('should clear user', function() {
+        expect(req.user).to.be.null;
+      });
+
+      it('should clear serialized user', function() {
+        expect(req.session['passport'].user).to.be.undefined;
+      });
+    });
+
     describe('existing session, but not passing a callback argument', function() {
       var passport = new Passport();
       passport.serializeUser(function(user, done) {