From: mike@... (Mike Stok)
Date: 2003-06-19T20:42:37+09:00
Subject: Re: Test::Unit:  assert in loop ?

In article <vyu1amiai0.fsf@pjakkur.iar.se>,
Johan Holmberg  <holmberg@iar.se> wrote:

[...]

>    require 'test/unit'
>
>    class TC_basic < Test::Unit::TestCase
>        @@table = [
>            [1,    6,    7],
>            [8,    3,   11],  # is ok
>            [100, 20,  120],
>            [-10, 20,   11],  # will cause error
>        ]
>
>        def test_plus
>            for a, b, sum in @@table
>                assert_equal( sum, a+b )
>            end
>        end
>    end
>
>
>The problem I'm having is that when an error occur, it is hard to tell
>which iteration that caused the error. The example above gives the error:
>
>    Loaded suite TC_table_driven
>    Started
>    F
>    Finished in 0.0082 seconds.
>
>      1) Failure!!!
>    test_plus(TC_basic) [TC_table_driven.rb:13]:
>    <11> expected but was
>    <10>
>
>    1 tests, 4 assertions, 1 failures, 0 errors
>
>It is impossible for me to tell which entry in @@table that caused the
>error. I don't know if there is some other way I could have written my
>tests to see this ?

You can add a message to the assertiom e.g.

    assert_equal( sum, a+b, "Testing #{a} + #{b} = #{sum}" )

and you get

  1) Failure!!!
test_plus(TC_basic) [trst.rb:13]:
Testing -10 + 20 = 11.
<11> expected but was
<10>

or something like this

  def test_plus
    @@table.each_with_index do |val, index|
      a, b, sum = val
      assert_equal( sum, a+b, "Testing #{a} + #{b} = #{sum} (row #{index})" )
    end
  end

might help (if you count rows from 0... :-)

Hope this helps,

Mike

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