Testing the error response using MockMvc and jsonPath ()

Question

I am trying to test Spring MVC controller error response with the following

this.mockMvc
    .perform(get("/healthChecks/9999"))
    .andExpect(status().isNotFound())
    .andExpect(jsonPath('error', is("Not Found")))
    .andExpect(jsonPath('timestamp', is(notNullValue())))
    .andExpect(jsonPath('status', is(404)))
    .andExpect(jsonPath('path', is(notNullValue())))

but the test fails with the exception: java.lang.IllegalArgumentException: json can not be null or empty on the first jsonPath statement.

When I twist this url, I get the following:

{
  "timestamp": 1470242437578,
  "status": 200,
  "error": "OK",
  "exception": "gov.noaa.ncei.gis.web.HealthCheckNotFoundException",
  "message": "could not find HealthCheck 9999.",
  "path": "/healthChecks/9999"
}

Can anyone help me understand what I'm doing wrong?