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Test2::Mock(3) |
User Contributed Perl Documentation |
Test2::Mock(3) |
Test2::Mock - Module for managing mocked classes and instances.
This module lets you add and override methods for any package temporarily. When
the instance is destroyed it will restore the package to its original state.
use Test2::Mock;
use MyClass;
my $mock = Test2::Mock->new(
track => $BOOL, # enable call tracking if desired
class => 'MyClass',
override => [
name => sub { 'fred' },
...
],
add => [
is_mocked => sub { 1 }
...
],
...
);
# Unmock the 'name' sub
$mock->restore('name');
...
$mock = undef; # Will remove all the mocking
- $mock = Test2::Mock->new(class => $CLASS, ...)
- This will create a new instance of Test2::Mock that manages mocking for
the specified $CLASS.
Any "Test2::Mock" method can
be used as a constructor argument, each should be followed by an
arrayref of arguments to be used within the method. For instance the
"add()" method:
my $mock = Test2::Mock->new(
class => 'AClass',
add => [foo => sub { 'foo' }],
);
is identical to this:
my $mock = Test2::Mock->new(
class => 'AClass',
);
$mock->add(foo => sub { 'foo' });
- $mock->track($bool)
- Turn tracking on or off. Any sub added/overridden/set when tracking is on
will log every call in a hash retrievable via
"$mock->tracking". Changing the
tracking toggle will not affect subs already altered, but will affect any
additional alterations.
- $hashref = $mock->sub_tracking
- The tracking data looks like this:
{
sub_name => [
{sub_name => $sub_name, sub_ref => $mock_subref, args => [... copy of @_ from the call ... ]},
...,
...,
],
}
Unlike call_tracking, this lists all calls by sub, so you can
choose to only look at the sub specific calls.
Please note: The hashref items with the subname and
args are shared with call_tracking, modifying one modifies the other, so
copy first!
- $arrayref = $mock->call_tracking
- The tracking data looks like this:
[
{sub_name => $sub_name, sub_ref => $mock_subref, args => [... copy of @_ from the call ... ]},
...,
...,
]
Unlike sub_tracking this lists all calls to any mocked sub, in
the order they were called. To filter by sub use sub_tracking.
Please note: The hashref items with the subname and
args are shared with sub_tracking, modifying one modifies the other, so
copy first!
- $mock->clear_sub_tracking()
- $mock->clear_sub_tracking(\@subnames)
- Clear tracking data. With no arguments ALL tracking data is cleared. When
arguments are provided then only those specific keys will be cleared.
- $mock->clear_call_tracking()
- Clear all items from call_tracking.
- $mock->add('symbol' => ..., 'symbol2' => ...)
- $mock->override('symbol1' => ..., 'symbol2' => ...)
- $mock->set('symbol1' => ..., 'symbol2' => ...)
- "add()" and
"override()" are the primary ways to
add/modify methods for a class. Both accept the exact same type of
arguments. The difference is that
"override" will fail unless the symbol
you are overriding already exists, "add"
on the other hand will fail if the symbol does already exist.
"set()" was more recently
added for cases where you may not know if the sub already exists. These
cases are rare, and set should be avoided (think of it like 'no
strict'). However there are valid use cases, so it was added.
Note: Think of override as a push operation. If you
call override on the same symbol multiple times it will track that. You
can use "restore()" as a pop operation
to go back to the previous mock.
"reset" can be used to remove all the
mocking for a symbol.
Arguments must be a symbol name, with optional sigil, followed
by a new specification of the symbol. If no sigil is specified then
'&' (sub) is assumed. A simple example of overriding a sub:
$mock->override(foo => sub { 'overridden foo' });
my $val = $class->foo; # Runs our override
# $val is now set to 'overridden foo'
You can also simply provide a value and it will be wrapped in
a sub for you:
$mock->override( foo => 'foo' );
The example above will generate a sub that always returns the
string 'foo'.
There are three *special* values that can be used to generate
accessors:
$mock->add(
name => 'rw', # Generates a read/write accessor
age => 'ro', # Generates a read only accessor
size => 'wo', # Generates a write only accessor
);
If you want to have a sub that actually returns one of the
three special strings, or that returns a coderef, you can use a hashref
as the spec:
my $ref = sub { 'my sub' };
$mock->add(
rw_string => { val => 'rw' },
ro_string => { val => 'ro' },
wo_string => { val => 'wo' },
coderef => { val => $ref }, # the coderef method returns $ref each time
);
You can also override/add other symbol types, such as
hash:
package Foo;
...
$mock->add('%foo' => {a => 1});
print $Foo::foo{a}; # prints '1'
You can also tell mock to deduce the symbol type for the
add/override from the reference, rules are similar to glob
assignments:
$mock->add(
-foo => sub { 'foo' }, # Adds the &foo sub to the package
-foo => { foo => 1 }, # Adds the %foo hash to the package
-foo => [ 'f', 'o', 'o' ], # Adds the @foo array to the package
-foo => \"foo", # Adds the $foo scalar to the package
);
- $mock->restore($SYMBOL)
- Restore the symbol to what it was before the last override. If the symbol
was recently added this will remove it. If the symbol has been overridden
multiple times this will ONLY restore it to the previous state. Think of
"override" as a push operation, and
"restore" as the pop operation.
- $mock->reset($SYMBOL)
- Remove all mocking of the symbol and restore the original symbol. If the
symbol was initially added then it will be completely removed.
- $mock->orig($SYMBOL)
- This will return the original symbol, before any mocking. For symbols that
were added this will return undef.
- $mock->current($SYMBOL)
- This will return the current symbol.
- $mock->reset_all
- Remove all added symbols, and restore all overridden symbols to their
originals.
- $mock->add_constructor($NAME => $TYPE)
- $mock->override_constructor($NAME => $TYPE)
- This can be used to inject constructors. The first argument should be the
name of the constructor. The second argument specifies the constructor
type.
The "hash" type is the most
common, all arguments are used to create a new hash that is blessed.
hash => sub {
my ($class, %params) = @_;
return bless \%params, $class;
};
The "array" type is similar
to the hash type, but accepts a list instead of key/value pairs:
array => sub {
my ($class, @params) = @_;
return bless \@params, $class;
};
The "ref" type takes a
reference and blesses it. This will modify your original input
argument.
ref => sub {
my ($class, $params) = @_;
return bless $params, $class;
};
The "ref_copy" type will
copy your reference and bless the copy:
ref_copy => sub {
my ($class, $params) = @_;
my $type = reftype($params);
return bless {%$params}, $class
if $type eq 'HASH';
return bless [@$params], $class
if $type eq 'ARRAY';
croak "Not sure how to construct a '$class' from '$params'";
};
- $mock->before($NAME, sub { ... })
- This will replace the original sub $NAME with a
new sub that calls your custom code just before calling the original
method. The return from your custom sub is ignored. Your sub and the
original both get the unmodified arguments.
- $mock->after($NAME, sub { ... })
- This is similar to before, except your callback runs after the original
code. The return from your callback is ignored.
- $mock->around($NAME, sub { ... })
- This gives you the chance to wrap the original sub:
$mock->around(foo => sub {
my $orig = shift;
my $self = shift;
my (@args) = @_;
...
$self->$orig(@args);
...
return ...;
});
The original sub is passed in as the first argument, even
before $self. You are responsible for making
sure your wrapper sub returns the correct thing.
- $mock->autoload
- This will inject an "AUTOLOAD" sub into
the class. This autoload will automatically generate read-write accessors
for any sub called that does not already exist.
- $mock->block_load
- This will prevent the real class from loading until the mock is destroyed.
This will fail if the class is already loaded. This will let you mock a
class completely without loading the original module.
- $pm_file = $mock->file
- This returns the relative path to the file for the module. This
corresponds to the %INC entry.
- $bool = $mock->purge_on_destroy($bool)
- When true, this will cause the package stash to be completely obliterated
when the mock object falls out of scope or is otherwise destroyed. You do
not normally want this.
- $stash = $mock->stash
- This returns the stash for the class being mocked. This is the equivalent
of:
my $stash = \%{"${class}\::"};
This saves you from needing to turn off strict.
- $class = $mock->class
- The class being mocked by this instance.
- $p = $mock->parent
- If you mock a class twice the first instance is the parent, the second is
the child. This prevents the parent from being destroyed before the child,
which would lead to a very unpleasant situation.
- $c = $mock->child
- Returns the child mock, if any.
The source code repository for Test2-Suite can be found at
<https://github.com/Test-More/Test2-Suite/>.
- Chad Granum <exodist@cpan.org>
- Chad Granum <exodist@cpan.org>
Copyright 2018 Chad Granum <exodist@cpan.org>.
This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.
See <https://dev.perl.org/licenses/>
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