ActiveSupport::Testing::FileFixtures

Adds simple access to sample files called file fixtures. File fixtures are normal files stored in ActiveSupport::TestCase.file_fixture_path.

File fixtures are represented as Pathname objects. This makes it easy to extract specific information:

file_fixture("example.txt").read # get the file's content
file_fixture("example.mp3").size # get the file size
Methods
F
Instance Public methods
file_fixture(fixture_name)

Returns a Pathname to the fixture file named fixture_name.

Raises ArgumentError if fixture_name can't be found.

Source: show | on GitHub 

# File activesupport/lib/active_support/testing/file_fixtures.rb, line 22
def file_fixture(fixture_name)
  path = Pathname.new(File.join(file_fixture_path, fixture_name))

  if path.exist?
    path
  else
    msg = "the directory '%s' does not contain a file named '%s'"
    raise ArgumentError, msg % [file_fixture_path, fixture_name]
  end
end