class FakeDibelsResultGenerator

  def initialize(student)
    @dates = (2010..2015).to_a.shuffle
    @student = student
  end

  def dibels_assessment_id
    @assessment_id ||= Assessment.find_by_family('DIBELS').id
  end

  def next
    {
      assessment_id: dibels_assessment_id,
      date_taken: DateTime.new(@dates.pop, 5, 15),
      performance_level: ["Intensive", "Strategic", "Core", "Benchmark", "CORE", nil].sample,
      student_id: @student.id
    }
  end
end

class FakeDibelsResultGenerator

  def initialize(student)
    @dates = (2010..2015).to_a.shuffle
    @student = student
  end

  def dibels_assessment_id
    @assessment_id ||= Assessment.find_by_family('DIBELS').id
  end

  def next
    {
      assessment_id: dibels_assessment_id,
      date_taken: DateTime.new(@dates.pop, 5, 15),
      performance_level: ["Intensive", "Strategic", "Core"].sample,
      student_id: @student.id
    }
  end
end

Update DIBELS demo data generator to remove nil, duplicate CORE and Benchmark, which isn't used
Update DIBELS demo data generator to remove nil, duplicate CORE and Benchmark, which isn't used