perl - 如何在Perl中为简单的I/O子例程创建单元测试

Question

ErrorLibrary.pm:

package Artopi::Builder::ErrorLibrary;

use strict;
use warnings;    

use constant {
    # wiki link included as a variable in this example
    CABLING_ERROR => {
    errorCode => 561,
    message => "cabling is not correct\n\n ",
    t => { template => 'disabled'},
    page =>'http://w.error-sol.com/index/Builder/ErrorCodes/_CABLING_ERROR',
    },
};

这是我要测试的error_post方法。我正在尝试进行单元测试，以便预期的输出是正确的。我当前的测试无法正确编译，我看不到代码的主要错误。这可能是我应该能够看到/知道的东西。

ErrorPost.pm:

package Artopi::Builder::ErrorPost;

use strict;
use warnings;
use Artopi::Builder::ErrorLibrary;


# takes error name as a param and prints out the message contained in the error hash.
sub error_post {

    my($error) = @_;
    print ($error->{ message });  

}
1;

以下是我提出的当前测试。但这给我一个错误，说:“/ErrorPost.pm第12行使用“strict refs”时，不能将字符串Artopi::Builder::ErrorPost用作HASH ref

error_post.t :
    my $error = Artopi::Builder::ErrorLibrary->CABLING_ERROR; 
    # expected values
    my $exp_output = ($error->{message});
    my $exp_input =  Artopi::Builder::ErrorLibrary->CABLING_ERROR;

    # input value as a parameter of error_post method
    my $error_in = Artropi::Builder::ErrorPost->error_post($exp_input);

    # checking that exp_input matches the expected output after the output has
    # been passed through the error_post method
    is($error_in, qr/$exp_output/, 'This is the correct output');   

有什么建议？ :)

Answer 1

您可以使用Test::Output测试打印的内容。

use Test::More;
use Test::Output;

sub error_post {
    my ($error) = @_;
    print( $error->{message} );
}

stdout_is { error_post( { message => 'foo' } ) } "foo", 
  'the error message is correct';

# equivalent without the bare block/map-ish syntax
stdout_is(
    sub { error_post( { message => 'foo' } ) },
    "foo",
    'the error message is correct'
);

# and using like
stdout_like { error_post($error) } qr/foo/,
  'the error message looks correct';

done_testing;

在这种情况下，根本不会测试您的子返回值。如果两者都需要，则必须将其保存在匿名子目录中，然后再进行测试。

my $rv;
stdout_is { $rv = error_post( { message => 'foo' } ) } "foo", 
  'the error message is correct';
is $rv, 'expected', '... and the return value is too';

Test::Output在幕后使用 Capture::Tiny，如果您只需要使用不受控制的代码来输出，这很好。