From: Johan Holmberg <holmberg@...>
Date: 2003-06-19T20:22:25+09:00
Subject: Test::Unit:  assert in loop ?


Hi !

Sometimes I find it convenient to have some of my unit tests
table-driven, rather than just straight lines of code. An example:

    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 ?

If not, I think one way for Test::Unit to handle this better would be
to indicate which of all calls to 'assert_equal' on line 13 that
caused the error (the first call, the second, the third, ....).
(some of the unit-test-modules for Perl does it that way)

I'm running (almost) the latest Test::Unit from Rubys CVS-archive.

/Johan Holmberg