Hi all,
This testing problem has been a sink for time today, and is still
unresolved.
Basically I have some unit tests that test simple functions (example
below)
that depend on join operations in a habtm relationship, and I suspect I
am
getting “false” failures, i.e ones that do not logically make any sense.
I
need fresh sets of eyes to take a look and see if I’m mising something
(my
error, rails bug?, mysql bug?).
It’s almost as though there is a race condition somewhere, or an
unreliable
SQL transaction.
def reservations
called by User object, returns count of reservations with associated
Zimp
objects
Zimp and User are AR classes mapped to MySQL schema shown later
below.
count = 0
self.zimps.each { |x| count += x.reserved.to_i }
count
end
A typical unit test for this function would be to create a User object
and
call the function, and check the return result
def test_working
@user=User.find(:first)
assert_equal 2, @user.reservations
end
For the test data loaded from the fixtures below, two records should be
returned, and the result should be 2. 90% of the time in testing this
is what
happens.
But sometimes this will fail with a result of zero (no matching records,
i.e.
the join operation produced no output). “Sometimes” means that
typically in
reptitive runs in the same environment it will continue to fail, until I
make
unrelated code changes, e.g. adding logger output, adding more code
somewhere
else, adding a test. etc.
I have tried running tests with rake, from within the radrails
environment,
from script/console, and with a coverage tool. Eventually I have
reproduced
the failure in multiple environments.
I have included most the information I think could be of use, including
the
test_helper.rb configuration, including a mod that disables constraint
checking in SQL (without this, the tests fail).
At a loss…
thanks
Chris
================== Extra info ===========
The SQL produced by the reservations function is:
SELECT * FROM zimps LEFT JOIN users_zimps ON zimps.id =
users_zimps.zimp_id
WHERE (users_zimps.user_id = 5 )
SCHEMA
CREATE TABLE users (
id int(11) NOT NULL auto_increment,
[…]
PRIMARY KEY (id)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
CREATE TABLE users_zimps (
zimp_id int(10) unsigned NOT NULL default ‘0’,
user_id int(10) unsigned NOT NULL default ‘0’,
reserved int(10) unsigned NOT NULL default ‘1’,
KEY fk_reservations_zimp (zimp_id),
KEY fk_reservations_user USING BTREE (user_id)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
CREATE TABLE zimps (
id int(11) NOT NULL auto_increment,
[…]
PRIMARY KEY (id),
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
users_zimps.yml
alice_buys_chris_bday_qty1:
zimp_id: 1
user_id: 5
reserved: 1
alice_buys_chris_bday_qty2:
zimp_id: 3
user_id: 5
reserved: 1
users.yml
otipher:
id: 1
bunky:
id: 2
email_bob:
id: 3
email_sally:
id: 4
alice:
id: 5
zimps.yml
otipher_bday_codebook:
id: 1
otipher_bday_headfirst:
id: 2
otipher_bday_cookbook:
id: 3
test_helper.rb
ENV[“RAILS_ENV”] = “test”
require File.expand_path(File.dirname(FILE) +
“/…/config/environment”)
require ‘test_help’
require ‘logger’
class Test::Unit::TestCase
self.use_transactional_fixtures = true
self.use_instantiated_fixtures = false
From http://rails.techno-weenie.net/tip/2005/11/20/log_within_tests
def logger
RAILS_DEFAULT_LOGGER
end
end
from
http://wiki.rubyonrails.com/rails/pages/DisableForeignKeyChecksUnderMySql
class Fixtures
alias :original_delete_existing_fixtures :delete_existing_fixtures
alias :original_insert_fixtures :insert_fixtures
def delete_existing_fixtures
@connection.update "SET FOREIGN_KEY_CHECKS = 0", 'Fixtures
deactivate
foreign key checks.';
original_delete_existing_fixtures
@connection.update “SET FOREIGN_KEY_CHECKS = 1”, ‘Fixtures
activate
foreign key checks.’;
end
def insert_fixtures
@connection.update "SET FOREIGN_KEY_CHECKS = 0", 'Fixtures
deactivate
foreign key checks.';
original_insert_fixtures
@connection.update “SET FOREIGN_KEY_CHECKS = 1”, ‘Fixtures
activate
foreign key checks.’;
end
end