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  3. perl-Test-NoWarnings
  4. Test::NoWarnings(3pm)

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Test::NoWarnings(3) User Contributed Perl Documentation Test::NoWarnings(3)

NAME

Test::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::NoWarnings 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 automatic 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:

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 '')
the message passed to "warn",
a full dump of the stack when warn was called, courtesy of the "Carp" module

EXPORTABLE 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 emitted.

  • $warn->getTestName

    Get the name of the test that executed before the warning was emitted.

PITFALLS

When counting your tests for the plan, don't forget to include the test that runs automatically when your script ends.

BUGS

None that I know of.

HISTORY

This was previously known as Test::Warn::None

SEE ALSO

Test::Builder, Test::Warn

AUTHOR

Written by Fergal Daly <fergal@esatclear.ie>.

COPYRIGHT

Copyright 2003 by Fergal Daly <fergal@esatclear.ie>.

This program is free software and comes with no warranty. It is distributed under the LGPL license

See the file LGPL included in this distribution or http://www.fsf.org/licenses/licenses.html.

2007-10-20 perl v5.10.1