def do_GET_day(self, conn: DatabaseConnection, date: str):
         """Show single Day."""
-        day = Day.by_date(conn, date)
+        day = Day.by_date(conn, date, create=True)
         return self.server.jinja.get_template('day.html').render(day=day)
 
     def do_POST(self):
 
         """Test /day response."""
         conn = HTTPConnection(*self.httpd.server_address)
         conn.request('GET', '/day')
-        response = conn.getresponse()
-        self.assertEqual(response.status, 200)
+        self.assertEqual(conn.getresponse().status, 200)
+        conn.request('GET', '/day?date=FOO')
+        self.assertEqual(conn.getresponse().status, 400)
 
     def tearDown(self):
         self.httpd.shutdown()