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# Coverage provides coverage measurement feature for Ruby. This feature is
# experimental, so these APIs may be changed in future.
#
# # Usage
#
# 1.  require "coverage"
# 2.  do Coverage.start
# 3.  require or load Ruby source file
# 4.  Coverage.result will return a hash that contains filename as key and
#     coverage array as value. A coverage array gives, for each line, the number
#     of line execution by the interpreter. A `nil` value means coverage is
#     disabled for this line (lines like `else` and `end`).
#
#
# # Example
#
#     [foo.rb]
#     s = 0
#     10.times do |x|
#       s += x
#     end
#
#     if s == 45
#       p :ok
#     else
#       p :ng
#     end
#     [EOF]
#
#     require "coverage"
#     Coverage.start
#     require "foo.rb"
#     p Coverage.result  #=> {"foo.rb"=>[1, 1, 10, nil, nil, 1, 1, nil, 0, nil]}
#
module Coverage
  def self.line_stub: () -> Array[Integer?]

  # Returns a hash that contains filename as key and coverage array as value. This
  # is the same as `Coverage.result(stop: false, clear: false)`.
  #
  #     {
  #       "file.rb" => [1, 2, nil],
  #       ...
  #     }
  #
  def self.peek_result: () -> Hash[String, untyped]

  # Returns a hash that contains filename as key and coverage array as value. If
  # `clear` is true, it clears the counters to zero. If `stop` is true, it
  # disables coverage measurement.
  #
  def self.result: (?stop: boolish, ?clear: boolish) -> Hash[String, untyped]

  # Returns true if coverage stats are currently being collected (after
  # Coverage.start call, but before Coverage.result call)
  #
  def self.running?: () -> bool

  # Enables coverage measurement.
  #
  def self.start: (?lines: boolish, ?branches: boolish, ?methods: boolish, ?oneshot_lines: boolish) -> nil
end