使用 minitest 测试正则表达式

Question

Assuming a shared method like:

  def sanitize_spaces(dirty_attribute)
    dirty_attribute = dirty_attribute.gsub(/\s+/, "")
  end

what kind of a minitest should be written? Naturally, one could test the method that calls this method, but that sort of buries the test within another. The goal is to have a mechanism to test this individual method on its own.

Answer 1

I don't think this method should be public (presumably you're just trying to give a name to a piece of logic so that it is easier to read), and if it is not public then I would not test it (you're testing implementation details).

But if the sanitize code you give is an example of some larger piece of logic, or it's a widely used helper method you could do something like this:

(I assume that the method is wrapped in a class called MySanitizer )

require "minitest/autorun"

class TestMySanitizer < Minitest::Test
  def setup
    @sanitizer = MySanitizer.new
  end

  def test_that_return_value_is_correct
    string_to_be_sanitized = "O H A I  \t\t\n   !"
    assert_equal "OHAI!", sanitizer.sanitize_spaces(string_to_be_sanitized)
  end

  def test_that_nowhitespace_input_is_unaffected
    nowhitespace = "OHAI!"
    assert_equal nowhitespace, sanitizer.sanitize_spaces(nowhitespace)
  end
end

Theoretically you could go further and have tests that include every form of whitespace and non-whitespace character, but your testing (automated or otherwise) is unlikely to be better than that which is already in place in the Ruby standard library for gsub, so it is not particularly useful to verify anything beyond the fact that there is something there which affects whitespace.