NAME Devel::StrictMode - determine whether strict (but slow) tests should be enabled SYNOPSIS package MyClass; use Moose; use Devel::StrictMode; has input_data => ( is => 'ro', isa => STRICT ? "HashRef[ArrayRef[Str]]" : "HashRef", required => 1, ); DESCRIPTION This module provides you with a constant `STRICT` which you can use to determine whether additional strict (but slow) runtime tests are executed by your code. `STRICT` is true if any of the following environment variables have been set to true: PERL_STRICT EXTENDED_TESTING AUTHOR_TESTING RELEASE_TESTING `STRICT` is false otherwise. It is anticipated that you might set one or more of the above variables to true while running your test suite, but leave them all false in your production scenario. Although not exported by default, a constant `LAX` is also provided, which returns the opposite of `STRICT`. Using STRICT with Moose/Moo/Mouse attributes Type constraint checks (`isa`) are conducted at run time. Slow checks can slow down your constructor and accessors. As shown above, `STRICT` can be used to alternate between a slower by stricter type constraint check, and a faster but looser one. Don't try this if your attribute coerces. It will subtly break things. Using STRICT to perform assertions in function and method calls You may protect blocks of assertions with an `if (STRICT) { ... }` conditional to ensure that they only run in your testing environment. sub fibonacci { my $n = $_[0]; if (STRICT) { die "expected exactly one argument" unless @_ == 1; die "expected argument to be a natural number" unless $n =~ /\A[0-9]+\z/; } $n < 2 ? $n : fibonacci($n-1)+fibonacci($n-2); } Because `STRICT` is a constant, the Perl compiler will completely optimize away the `if` block when running in your production environment. Using STRICT with pragmata Thanks to if it's easy to use `STRICT` to conditionally load pragmata. use Devel::StrictMode; use strict; use warnings STRICT ? qw(FATAL all) : qw(all); no if STRICT, "bareword::filehandles"; no if STRICT, "autovivification"; See also autovivification, bareword::filehandles, indirect, multidimensional, etc. BUGS Please report any bugs to . SEE ALSO strictures. AUTHOR Toby Inkster . COPYRIGHT AND LICENCE This software is copyright (c) 2014 by Toby Inkster. This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself. DISCLAIMER OF WARRANTIES THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.