module ActiveSupport::Testing::TestsWithoutAssertions

def after_teardown

:nodoc:
This is helpful in detecting broken tests that do not perform intended assertions.

Warns when a test case does not perform any assertions. 
def after_teardown
  super
  if assertions.zero? && !skipped? && !error?
    file, line = method(name).source_location
    warn "Test is missing assertions: `#{name}` #{file}:#{line}"
  end
end