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

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


NAME

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


VERSION

Version 1.12


SYNOPSIS


    use Carp::Assert::More;

    my $obj = My::Object;

    assert_isa( $obj, 'My::Object', 'Got back a correct object' );


DESCRIPTION

Carp::Assert::More is a set of wrappers around the the Carp::Assert manpage 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.


SIMPLE ASSERTIONS

assert_is( $string, $match [,$name] )

Asserts that $string matches $match.

assert_isnt( $string, $unmatch [,$name] )

Asserts that $string does NOT match $unmatch.

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

Asserts that $string matches qr/regex/.

assert_defined( $this [, $name] )

Asserts that $this is defined.

assert_nonblank( $this [, $name] )

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


NUMERIC ASSERTIONS

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_nonnegative( $this [, $name ] )

Asserts that the numeric value of $this is greater than or equal to zero. Since non-numeric strings evaluate to zero, this means that any non-numeric string will pass.


    assert_nonnegative( 0 );    # pass

    assert_nonnegative( -14 );  # FAIL

    assert_nonnegative( '14.' );  # pass

    assert_nonnegative( 'dog' );  # pass

assert_negative( $this [, $name ] )

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


    assert_negative( 0 );       # FAIL

    assert_negative( -14 );     # pass

    assert_negative( '14.' );   # FAIL

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.' ); # FAIL

    assert_positive_integer( '14' );  # pass

assert_nonnegative_integer( $this [, $name ] )

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


    assert_nonnegative_integer( 0 );    # pass

    assert_nonnegative_integer( -14 );  # pass

    assert_nonnegative_integer( '14.' );  # FAIL

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


REFERENCE ASSERTIONS

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

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

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_nonref( $this [, $name ] )

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

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.


SET AND HASH MEMBERSHIP

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 %hash is indeed a hash, and that $key exists in %hash, or that all of the keys in @keylist exist in %hash.


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

    assert_exists( \%custinfo, [qw( name addr phone )],

                            'Customer has name, address and phone' );

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

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

Asserts that %hash is indeed a hash, and that $key does NOT exist in %hash, or that none of the keys in @keylist exist in %hash.


    assert_lacks( \%users, 'root', 'Root is not in the user table' );

    assert_lacks( \%users, [qw( root admin nobody )], 'No bad usernames found' );


UTILITY ASSERTIONS

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.


COPYRIGHT

Copyright (c) 2005 Andy Lester. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.


ACKNOWLEDGEMENTS

Thanks to Bob Diss, Pete Krawczyk, David Storrs, Dan Friedman, and Allard Hoeve for code and fixes.

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