Add strict cookie tests

Fixes #5525

src/server/http/__tests__/index.js

@@ -0,0 +1,39 @@
+import expect from 'expect.js';
+import KbnServer from '../../KbnServer';
+
+describe('cookie validation', function () {
+  let kbnServer;
+  beforeEach(function () {
+    kbnServer = new KbnServer();
+    return kbnServer.ready();
+  });
+  afterEach(function () {
+    return kbnServer.close();
+  });
+
+  it('allows non-strict cookies', function (done) {
+    kbnServer.server.inject({
+      method: 'GET',
+      url: '/',
+      headers: {
+        cookie: 'test:80=value;test_80=value'
+      }
+    }, (res) => {
+      expect(res.payload).not.to.contain('Invalid cookie header');
+      done();
+    });
+  });
+
+  it('returns an error if the cookie can\'t be parsed', function (done) {
+    kbnServer.server.inject({
+      method: 'GET',
+      url: '/',
+      headers: {
+        cookie: 'a'
+      }
+    }, (res) =>  {
+      expect(res.payload).to.contain('Invalid cookie header');
+      done();
+    });
+  });
+});