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#!/usr/bin/perl
use Test::More tests => 15;
use strict;
use warnings;
use Test::Exception;
use DBI;
use DBD::Mock;
# This test is designed to expose the bug found in the DBD::Mock
# methods begin_work, commit and rollback (RT #66815), where a failing
# ->prepare invocation (returning nothing) is not detected and the
# undefined value resulting is used anyway. In this test, as in the
# example found in the wild, the failure is triggered by exhaustion of
# the session states.
#
# This is a list of sessions designed to engineer the right condition
# to trigger the bug. They all start with a dummy statement (so that
# there are at least two states) then the final statement is removed
# before it is passed to DBD::Mock::Session->new (which requires at
# least one state). The final statements are 'BEGIN WORK', 'COMMIT'
# and 'ROLLBACK', respectively.
#
# Hence, when the test tries to invoke the final state, the session
# will have run out and DBD::Mock->verify_statement will cause the
# prepare method to fail.
my @cases = (
'begin_work' => [
{
statement => 'SELECT something FROM somewhere',
results => [],
},
{
statement => 'BEGIN WORK',
results => [],
},
],
'commit' => [
{
statement => 'SELECT something FROM somewhere',
results => [],
},
{
statement => 'BEGIN WORK',
results => [],
},
{
statement => 'INSERT INTO foo (bar) VALUES (?);',
results => [],
bound_params => [1],
},
{
statement => 'COMMIT',
results => [],
},
],
'rollback' => [
{
statement => 'SELECT something FROM somewhere',
results => [],
},
{
statement => 'BEGIN WORK',
results => [],
},
{
statement => 'INSERT INTO foo (bar) VALUES (?);',
results => [],
bound_params => [1],
},
{
statement => 'ROLLBACK',
results => [],
},
],
);
while(@cases) {
my ($name, $states) = splice @cases, 0, 2;
my $case_name = "case $name";
my $dbh = DBI->connect('dbi:Mock:', '', '',
{ PrintError => 0,
RaiseError => 1 });
# Add all but the last state of the expected session
my $missing_state = pop @$states;
my $num_states = @$states;
$dbh->{mock_session} = DBD::Mock::Session->new($name => @$states);
# Execute the initial dummy statement.
my $state = $states->[0];
my $sth = $dbh->prepare($state->{statement});
ok $sth,
"$case_name: prepare statement";
ok $sth->execute(),
"$case_name: execute statement";
# Now try and do the next steps in @session, but using the
# appropriate transaction methods directly. This should fail when
# the session is exhausted with a useful message. (The original
# bug meant that the message got clobbered by "Can't call method
# 'execute' on an undefined value".)
throws_ok {
# This stlibatement is always the same.
ok $dbh->begin_work,
"$case_name: start transaction";
my $state = $states->[2];
my $sth = $dbh->prepare($state->{statement});
ok $sth,
"$case_name: prepare statement";
ok $sth->execute(@{$state->{bound_params}}),
"$case_name: execute statement";
# get the final operation from the session
my $operation = lc $missing_state->{statement};
ok $dbh->$operation,
"$case_name: $operation transaction";
} qr/\QSession states exhausted, only '$num_states' in DBD::Mock::Session\E/;
}
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