module SimpleCov::Combine

def combine(combiner_module, coverage_a, coverage_b)
  return existing_coverage(coverage_a, coverage_b) if empty_coverage?(coverage_a, coverage_b)
  combiner_module.combine(coverage_a, coverage_b)
end

def empty_coverage?(coverage_a, coverage_b)
  !(coverage_a && coverage_b)
end

def existing_coverage(coverage_a, coverage_b)
  coverage_a || coverage_b
end