module HexaPDF::TestUtils

def assert_method_invoked(object, name, *expected_values, check_block: false)

invocation of the method.
executing the block. +expected_values+ should contain arrays of arguments, one array for each
Asserts that the method +name+ of +object+ gets invoked with the +expected_values+ when 
def assert_method_invoked(object, name, *expected_values, check_block: false)
  args = []
  block = []
  object.define_singleton_method(name) {|*la, &lb| args << la; block << lb }
  yield
  assert_equal(expected_values, args, "Incorrect arguments for #{object.class}##{name}")
  block.each do |block_arg|
    assert_kind_of(Proc, block_arg, "Missing block for #{object.class}##{name}") if check_block
  end
ensure
  object.singleton_class.send(:remove_method, name)
end

def assert_operators(content, operators, only_names: false, range: 0..-1)

Asserts that the content string contains the operators. 
def assert_operators(content, operators, only_names: false, range: 0..-1)
  processor = OperatorRecorder.new
  HexaPDF::Content::Parser.new.parse(content, processor)
  result = processor.recorded_ops[range]
  result.map!(&:first) if only_names
  assert_equal(operators, result)
end

def collector(source)

Collects the result from the HexaPDF::Filter source into a binary string. 
def collector(source)
  str = ''.b
  while source.alive? && (data = source.resume)
    str << data
  end
  str
end

def feeder(string, len = string.length)

Creates a fiber that yields the given string in +len+ length parts. 
def feeder(string, len = string.length)
  Fiber.new do
    until string.empty?
      Fiber.yield(string.slice!(0, len).force_encoding('BINARY'))
    end
  end
end