String comparison in Ruby on Rails unit-test

Question

Hi,
my Ruby On Rails unit-test fails in a simple string comparison and I can't figure out why.

In the model TestItem, I have

doc = REXML::Document.new(data)
@bugtitle = doc.root.get_text("/bugzilla/bug/short_desc")

where data is a xml-string returned by a Net::HTTP::post request. The data looks good, and if I output @bugtitle it contains the expected string. In my unit-test, I have

  test "bugtitle" do
    ti = testitems(:one)
    assert_equal("different RID folder for gating x-ray correction images",ti.bugtitle)
  end

Surprisingly (at least for me) the test fails with the following output (copied verbatim from the shell):

  1) Failure:
 test_bugtitle(TestTest) [unit/testitem_test.rb:7]:
 <"different RID folder for gating x-ray correction images"> expected but was
 <"different RID folder for gating x-ray correction images">.

I'm at a loss here as to where this error comes from since the string do look identical to me. For what it's worth, this is with rails 2.3.4 and ruby 1.8.6 on Windows (don't get me started).

Answer 1

Those two seems identical, but you only see their representation after #inspect. You should check encoding and binary representation (if it's Ruby 1.9), maybe that's the problem.

Answer 2

Since MBO poked me into the right direction, here is the solution:

For debugging, I added a p @bugtitle.class into the model code, which revealed, that @bugtitle was an REXML::Text instance. The correct model code is:

doc = REXML::Document.new(data)
@bugtitle = doc.root.get_text("/bugzilla/bug/short_desc").to_s

With that modification the unit-test completes without failures.