/ 
Carp-Assert-More-1.02
River stage three • 9 direct dependents • 169 total dependents
/ Carp::Assert::More

NAME

Carp::Assert::More - convenience wrappers around Carp::Assert

VERSION

Version 1.02

$Header: /home/cvs/carp-assert-more/More.pm,v 1.18 2004/01/18 04:15:36 andy Exp $

SYNOPSIS

use Carp::Assert::More;

my $parser = HTML::Parser->new();
assert_isa( $parser, 'HTML::Parser', 'Got back a correct object' );

DESCRIPTION

Carp::Assert::More is a set of wrappers around the Carp::Assert functions to make the habit of writing assertions even easier.

Everything in here is effectively syntactic sugar. There's no technical reason to use

assert_isa( $foo, 'HTML::Lint' );

instead of

assert( defined $foo );
assert( ref($foo) eq 'HTML::Lint' );

other than readability and simplicity of the code.

My intent here is to make common assertions easy so that we as programmers have no excuse to not use them.

CAVEATS

I haven't specifically done anything to make Carp::Assert::More be backwards compatible with anything besides Perl 5.6.1, much less back to 5.004. Perhaps someone with better testing resources in that area can help me out here.

FUNCTIONS

Please note that there is no assert_string function. A string is just a non-reference, for which we have assert_nonref.

assert_fail( [$name] )

Assertion that always fails. assert_fail($msg) is exactly the same as calling assert(0,$msg), but it eliminates that case where you accidentally use assert($msg), which of course never fires.

assert_defined( $this [, $name] )

Asserts that $this is defined.

assert_nonref( $this [, $name ] )

Asserts that $this is not undef and not a reference.

assert_nonblank( $this [, $name] )

Asserts that $this is not blank and not a reference.

assert_integer( $this [, $name ] )

Asserts that $this is an integer, which may be zero or negative.

assert_integer( 0 );    # pass
assert_integer( -14 );  # pass
assert_integer( '14.' );  # FAIL

assert_nonzero( $this [, $name ] )

Asserts that the numeric value of $this is not zero.

assert_nonzero( 0 );    # FAIL
assert_nonzero( -14 );  # pass
assert_nonzero( '14.' );  # pass

Asserts that the numeric value of $this is not zero.

assert_positive( $this [, $name ] )

Asserts that the numeric value of $this is greater than zero.

assert_positive( 0 );    # FAIL
assert_positive( -14 );  # FAIL
assert_positive( '14.' );  # pass

assert_negative( $this [, $name ] )

Asserts that the numeric value of $this is less than zero.

assert_negative( 0 );    # FAIL
assert_negative( -14 );  # FAIL
assert_negative( '14.' );  # pass

assert_nonzero_integer( $this [, $name ] )

Asserts that the numeric value of $this is not zero, and that $this is an integer.

assert_nonzero_integer( 0 );    # FAIL
assert_nonzero_integer( -14 );  # pass
assert_nonzero_integer( '14.' );  # FAIL

assert_positive_integer( $this [, $name ] )

Asserts that the numeric value of $this is greater than zero, and that $this is an integer.

assert_positive_integer( 0 );    # FAIL
assert_positive_integer( -14 );  # FAIL
assert_positive_integer( '14.' );  # pass

assert_negative_integer( $this [, $name ] )

Asserts that the numeric value of $this is less than zero, and that $this is an integer.

assert_negative_integer( 0 );    # FAIL
assert_negative_integer( -14 );  # pass
assert_negative_integer( '14.' );  # FAIL

assert_nonempty( $this [, $name ] )

$this must be a ref to either a hash or an array. Asserts that that collection contains at least 1 element. Will assert (with its own message, not $name) unless given a hash or array ref. It is OK if $this has been blessed into objecthood, but the semantics of checking an object to see if it has keys (for a hashref) or returns >0 in scalar context (for an array ref) may not be what you want.

assert_nonempty( 0 );       # FAIL
assert_nonempty( 'foo' );   # FAIL
assert_nonempty( undef );   # FAIL
assert_nonempty( {} );      # FAIL
assert_nonempty( [] );      # FAIL
assert_nonempty( {foo=>1} );# pass
assert_nonempty( [1,2,3] ); # pass

assert_isa( $this, $type [, $name ] )

Asserts that $this is an object of type $type.

assert_like( $string, qr/regex/ [,$name] )

Asserts that $string matches qr/regex/.

assert_in( $string, \@inlist [,$name] );

Asserts that $string is defined and matches one of the elements of \@inlist.

\@inlist must be an array reference of defined strings.

assert_exists( \%hash, $key [,$name] )

assert_exists( \%hash, \@keylist [,$name] )

Asserts that $key exists in %hash, or that all of the keys in @keylist exist in %this.

assert_exists( \%custinfo, 'name', 'Customer has a name field' );

assert_exists( \%custinfo, [qw( name addr phone )],
                        'Customer has name, address and phone' );

assert_hashref( $ref [,$name] )

Asserts that $ref is defined, and is a reference to a (possibly empty) hash.

NB: This method returns false for objects, even those whose underlying data is a hashref. This is as it should be, under the assumptions that:

(a)

you shouldn't rely on the underlying data structure of a particular class, and

(b)

you should use assert_isa instead.

assert_listref( $ref [,$name] )

Asserts that $ref is defined, and is a reference to a (possibly empty) list.

NB: The same caveat about objects whose underlying structure is a hash (see assert_hashref) applies here; this method returns false even for objects whose underlying structure is an array.

AUTHOR

Andy Lester <andy@petdance.com>

ACKNOWLEDGEMENTS

Thanks to Pete Krawczyk, David Storrs and Dan Friedman for assert_ functions.