Test::NoWarnings(3) User Contributed Perl Documentation Test::NoWarnings(3)NAMETest::NoWarnings - Make sure you didn't emit any warnings while testing
SYNOPSIS
For scripts that have no plan
use Test::NoWarnings;
that's it, you don't need to do anything else
For scripts that look like
use Test::More tests => x;
change to
use Test::More tests => x + 1;
use Test::NoWarnings;
DESCRIPTION
In general, your tests shouldn't produce warnings. This modules causes
any warnings to be captured and stored. It automatically adds an extra
test that will run when your script ends to check that there were no
warnings. If there were any warings, the test will give a "not ok" and
diagnostics of where, when and what the warning was, including a stack
trace of what was going on when the it occurred.
If some of your tests are supposed to produce warnings then you should
be capturing and checking them with Test::Warn, that way Test::NoWarn‐
ings will not see them and so not complain.
The test is run by an "END" block in Test::NoWarnings. It will not be
run when any forked children exit.
USAGE
Simply by using the module, you automatically get an extra test at the
end of your script that checks that no warnings were emitted. So just
stick
use Test::NoWarnings;
at the top of your script and continue as normal.
If you want more control you can invoke the test manually at any time
with "had_no_warnings".
The warnings your test has generated so far are stored in an array. You
can look inside and clear this whenever you want with "warnings()" and
"clear_warnings", however, if you are doing this sort of thing then you
probably want to use Test::Warn in combination with Test::NoWarnings.
use vs require
You will almost always want to do
use Test::NoWarnings
If you do a "require" rather than a "use", then there will be no auto‐
matic test at the end of your script.
Output
If warning is captured during your test then the details will output as
part of the diagnostics. You will get:
o the number and name of the test that was executed just before the
warning (if no test had been executed these will be 0 and '')
o the message passed to "warn",
o a full dump of the stack when warn was called, courtesy of the "Carp"
module
By default, all warning messages will be emitted in one block at the
end of your test script.
The :early pragma
One common complaint from people using Test::NoWarnings is that all of
the warnings are emitted in one go at the end. While this is the safest
and most correct time to emit these diagnostics, it can make debugging
these warnings difficult.
As of Test::NoWarnings 1.04 you can provide an experimental ":early"
pragma when loading the module to force warnings to be thrown via diag
at the time that they actually occur.
use Test::NoWarnings ':early';
As this will cause the diag to be emitted against the previous test and
not the one in which the warning actually occurred it is recommended
that the pragma be turned on only for debugging and left off when not
needed.
FUNCTIONS
had_no_warnings
This checks that there have been warnings emitted by your test scripts.
Usually you will not call this explicitly as it is called automatically
when your script finishes.
clear_warnings
This will clear the array of warnings that have been captured. If the
array is empty then a call to "had_no_warnings()" will produce a pass
result.
warnings
This will return the array of warnings captured so far. Each element of
this array is an object containing information about the warning. The
following methods are available on these object.
· $warn->getMessage
Get the message that would been printed by the warning.
· $warn->getCarp
Get a stack trace of what was going on when the warning happened,
this stack trace is just a string generated by the Carp module.
· $warn->getTrace
Get a stack trace object generated by the Devel::StackTrace module.
This will return undef if Devel::StackTrace is not installed.
· $warn->getTest
Get the number of the test that executed before the warning was emit‐
ted.
· $warn->getTestName
Get the name of the test that executed before the warning was emit‐
ted.
PITFALLS
When counting your tests for the plan, don't forget to include the test
that runs automatically when your script ends.
SUPPORT
Bugs should be reported via the CPAN bug tracker at
<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Test-NoWarnings>
For other issues, contact the author.
HISTORY
This was previously known as Test::Warn::None
SEE ALSO
Test::Builder, Test::Warn
AUTHORS
Fergal Daly <fergal@esatclear.ie>
Adam Kennedy <adamk@cpan.org>
COPYRIGHT
Copyright 2003 - 2007 Fergal Daly.
Some parts copyright 2010 - 2011 Adam Kennedy.
This program is free software and comes with no warranty. It is dis‐
tributed under the LGPL license
See the file LGPL included in this distribution or
http://www.fsf.org/licenses/licenses.html.
perl v5.8.8 2011-12-01 Test::NoWarnings(3)
