Looker Unit Testing value in developmentg against a value in development

Question

I would like to write a unit test that checks whether a value in the development environment matched the value in production in Looker. At the moment I can check values against a static hardcoded value, but not able to check dynamically

test: 5_test_impacted_engineers_with_new_eng_levels{
  explore_source: fellow{
    column:impacted_engineers{
      field:fellow.count
    }

    filters: {
      field: fellow.eng_level
      value: "Eng1, Eng2, Eng3, Eng4, Eng5, Eng6, Eng7"


    }
    filters: {
      field:fellow_promotion_dates.impacted_engineers
      value: "yes"
    }

  }
##impacted engineers should not have had eng levels, yes?
  assert: expected_impacted_new_levels {
    expression: ${fellow.count}=0;;

  }
}