class RSpec::Matchers::BuiltIn::ChangeDetails

# File lib/rspec/matchers/built_in/change.rb, line 318
def initialize(matcher_name, receiver=nil, message=nil, &block)
  if receiver && !message
    raise(
      ArgumentError,
      "`change` requires either an object and message "                "(`change(obj, :msg)`) or a block (`change { }`). "                "You passed an object but no message."
    )
  end

  @matcher_name = matcher_name
  @receiver = receiver
  @message = message
  @value_proc = block
end

# File lib/rspec/matchers/built_in/change.rb, line 355
def actual_delta
  @actual_after - @actual_before
end

# File lib/rspec/matchers/built_in/change.rb, line 351
def changed?
  @actual_before != @actual_after
end

# File lib/rspec/matchers/built_in/change.rb, line 345
def perform_change(event_proc)
  @actual_before = evaluate_value_proc
  event_proc.call
  @actual_after = evaluate_value_proc
end

# File lib/rspec/matchers/built_in/change.rb, line 334
def value_representation
  @value_representation ||=
    if @message
      "##{@message}"
    elsif (value_block_snippet = extract_value_block_snippet)
      "`#{value_block_snippet}`"
    else
      'result'
    end
end