NAME

Test::Resub - Lexically scoped subroutine replacement for testing

SYNOPSIS

  #!/usr/bin/perl

  use Test::More tests => 4;
  use Test::Resub qw(resub);

  {
    package Somewhere;
    sub show {
      my ($class, $message) = @_;
      return "$class, $message";
    }
  }

  # sanity
  is( Somewhere->show('beyond the sea'), 'Somewhere, beyond the sea' );

  # scoped replacement of subroutine with argument capturing
  {
    my $rs = resub 'Somewhere::show', sub { 'hi' }, capture => 1;
    is( Somewhere->show('over the rainbow'), 'hi' );
    is_deeply( $rs->method_args, [['over the rainbow']] );
  }

  # scope ends, resub goes away, original code returns
  is( Somewhere->show('waiting for me'), 'Somewhere, waiting for me' );

DESCRIPTION

This module allows you to temporarily replace a subroutine/method with arbitrary code. Later, you can tell how many times was it called and with what arguments each time. You can also specify that the subroutine/method must get called, must not get called, or may be optionally called.

CONSTRUCTOR

    my $rs = resub 'package::method', sub { ... }, %args;

is equivalent to:

    my $rs = Test::Resub->new(
      name => 'package::method',
      code => sub { ... },
      %args,
    );

%args can be any of the following named arguments:

name

The function/method which is to be replaced.

code

The code reference which will replace name. Defaults to sub {}

capture

Boolean which indicates whether or not arguments should be captured. A warning is emitted if you try to look at args without specifying a "true" capture. Defaults to 0.

call

One of the following values (defaults to 'required'):

required

If the subroutine/method was never called when the Test::Resub object is destroyed, "not ok 1000" is printed to STDOUT.

forbidden

If the subroutine/method was called when the Test::Resub object is destroyed, "not ok 1000" is printed to STDOUT.

optional

It doesn't matter if the subroutine/method gets called. As a general rule, your tests should know whether or not a subroutine/method is going to get called, so avoid using this option if you can.

METHODS

called

Returns the number of times the replaced subroutine/method was called. The reset method clears this data.

was_called

Returns the total number of times the replaced subroutine/method was called. This data is not cleared by the reset method.

not_called

Returns true if the replaced subroutine/method was never called. The reset method clears this data.

reset

Clears the called, not_called, and args data.

args

Returns data on how the replaced subroutine/method was invoked. Examples:

  Invocations:                             C<args> returns:
  ----------------------------             -------------------------
    (none)                                   []
    foo('a');                                [['a']]
    foo('a', 'b'); foo('d');                 [['a', 'b'], ['d']]

named_args

Like args, but each invocation's arguments are returned in a hashref. Examples:

  Invocations:                             C<named_args> returns:
  ----------------------------             -------------------------
   (none)                                   []
   foo(a => 'b');                           [{a => 'b'}]

   foo(a => 'b', c => 'd'); foo(e => 'f');
                                            [{
                                              a => 'b', c => 'd',
                                            }, {
                                              e => 'f',
                                            }]

The arg_start_index argument specifes that a certain number of arguments are to be discarded. For example:

  my $rs = resub 'some_sub';
  ...
  some_sub('one', 'two', a => 1, b => 2);
  ...
  $rs->named_args(arg_start_index => 1);
  # returns ['two', {a => 1, b => 2}]

  $rs->named_args(arg_start_index => 2);
  # returns [{a => 1, b => 2}]

The scalars argument specifies that a certain number of scalar arguments precede the key/value arguments. For example:

  my $rs = resub 'some_sub';
  ...
  some_sub(3306, a => 'b', c => 123);
  some_sub(9158, a => 'z', c => 456);
  ...
  $rs->named_args(scalars => 1);
  # returns [3306, {a => 'b', c => 123},
  #          9158, {a => 'z', c => 456}]

Note that named_args(scalars => N) will yield N scalars plus one hashref per call regardless of how many arguments were passed to the subroutine/method. For example:

  my $rs = Test::Resub->new({name => 'some_sub'});
  ...
  some_sub('one argument only');
  some_sub('many', 'arguments', a => 1, b => 2);
  ...
  $rs->named_args(scalars => 2);
  # returns ['one argument only', undef, {},
  #          'many', 'arguments', {a => 1, b => 2}]

method_args

Like args, but the first argument of each invocation is thrown away. This is used when you're resub'ing an object or class method and you're not interested in testing the object or class argument. Examples:

  Invocations:                             C<method_args> returns:
  ----------------------------             -------------------------
    (none)                                   []
    $obj->foo('a');                          [['a']]
    Class->foo('a', 'b'); Class->foo('d');   [['a', 'b'], ['d']]

named_method_args

Like named_args, but the first argument of each invocation is thrown away. This is used when you're resub'ing an object or class method and the arguments are name/value pairs. Examples:

  Invocations:                             C<named_args> returns:
  ----------------------------             -------------------------
   (none)                                   []
   $obj->foo(a => 'b');                     [{a => 'b'}]

   $obj->foo(a => 'b', c => 'd');           [{
   Class->foo(e => 'f');                      a => 'b', c => 'd',
                                            }, {
                                              e => 'f',
                                            }]

named_method_args also takes a "scalars" named argument which specifies a number of scalar arguments preceding the name/value pairs of each invocation. It works just like named_args except that the first argument of each invocation is automatically discarded. For example:

  my $rs = resub 'SomeClass::some_sub';
  ...
  SomeClass->some_sub(3306, a => 'b', c => 123);
  SomeClass->some_sub(9158, a => 'z', c => 456);
  ...
  $rs->named_method_args(scalars => 1);
  # returns [3306, {a => 'b', c => 123},
  #          9158, {a => 'z', c => 456}]

Note: the first argument is automatically discarded before the optional arg_start_index parameter is applied. That is,

  my $rs = resub 'SomeClass::some_sub';
  ...
  SomeClass->some_sub('first', b => 2);
  ...
  $rs->named_method_args(arg_start_index => 1);
  # returns [{b => 2}]

HISTORY

Written at AirWave Wireless for internal testing, 2001-2007. Tidied up and released to CPAN in 2007.

AUTHORS

The development team at AirWave Wireless, http://www.airwave.com/. Please direct questions, comments, bugs, patches, etc. to cpan@airwave.com.