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.. index::
single: Cookbook; Class Constants
Class Constants
===============
When creating a test double for a class, Mockery does not create stubs out of
any class constants defined in the class we are mocking. Sometimes though, the
non-existence of these class constants, setup of the test, and the application
code itself, it can lead to undesired behavior, and even a PHP error:
``PHP Fatal error: Uncaught Error: Undefined class constant 'FOO' in ...``
While supporting class constants in Mockery would be possible, it does require
an awful lot of work, for a small number of use cases.
Named Mocks
-----------
We can, however, deal with these constants in a way supported by Mockery - by
using :ref:`creating-test-doubles-named-mocks`.
A named mock is a test double that has a name of the class we want to mock, but
under it is a stubbed out class that mimics the real class with canned responses.
Lets look at the following made up, but not impossible scenario:
.. code-block:: php
class Fetcher
{
const SUCCESS = 0;
const FAILURE = 1;
public static function fetch()
{
// Fetcher gets something for us from somewhere...
return self::SUCCESS;
}
}
class MyClass
{
public function doFetching()
{
$response = Fetcher::fetch();
if ($response == Fetcher::SUCCESS) {
echo "Thanks!" . PHP_EOL;
} else {
echo "Try again!" . PHP_EOL;
}
}
}
Our ``MyClass`` calls a ``Fetcher`` that fetches some resource from somewhere -
maybe it downloads a file from a remote web service. Our ``MyClass`` prints out
a response message depending on the response from the ``Fetcher::fetch()`` call.
When testing ``MyClass`` we don't really want ``Fetcher`` to go and download
random stuff from the internet every time we run our test suite. So we mock it
out:
.. code-block:: php
// Using alias: because fetch is called statically!
\Mockery::mock('alias:Fetcher')
->shouldReceive('fetch')
->andReturn(0);
$myClass = new MyClass();
$myClass->doFetching();
If we run this, our test will error out with a nasty
``PHP Fatal error: Uncaught Error: Undefined class constant 'SUCCESS' in ..``.
Here's how a ``namedMock()`` can help us in a situation like this.
We create a stub for the ``Fetcher`` class, stubbing out the class constants,
and then use ``namedMock()`` to create a mock named ``Fetcher`` based on our
stub:
.. code-block:: php
class FetcherStub
{
const SUCCESS = 0;
const FAILURE = 1;
}
\Mockery::namedMock('Fetcher', 'FetcherStub')
->shouldReceive('fetch')
->andReturn(0);
$myClass = new MyClass();
$myClass->doFetching();
This works because under the hood, Mockery creates a class called ``Fetcher``
that extends ``FetcherStub``.
The same approach will work even if ``Fetcher::fetch()`` is not a static
dependency:
.. code-block:: php
class Fetcher
{
const SUCCESS = 0;
const FAILURE = 1;
public function fetch()
{
// Fetcher gets something for us from somewhere...
return self::SUCCESS;
}
}
class MyClass
{
public function doFetching($fetcher)
{
$response = $fetcher->fetch();
if ($response == Fetcher::SUCCESS) {
echo "Thanks!" . PHP_EOL;
} else {
echo "Try again!" . PHP_EOL;
}
}
}
And the test will have something like this:
.. code-block:: php
class FetcherStub
{
const SUCCESS = 0;
const FAILURE = 1;
}
$mock = \Mockery::mock('Fetcher', 'FetcherStub')
$mock->shouldReceive('fetch')
->andReturn(0);
$myClass = new MyClass();
$myClass->doFetching($mock);
Constants Map
-------------
Another way of mocking class constants can be with the use of the constants map configuration.
Given a class with constants:
.. code-block:: php
class Fetcher
{
const SUCCESS = 0;
const FAILURE = 1;
public function fetch()
{
// Fetcher gets something for us from somewhere...
return self::SUCCESS;
}
}
It can be mocked with:
.. code-block:: php
\Mockery::getConfiguration()->setConstantsMap([
'Fetcher' => [
'SUCCESS' => 'success',
'FAILURE' => 'fail',
]
]);
$mock = \Mockery::mock('Fetcher');
var_dump($mock::SUCCESS); // (string) 'success'
var_dump($mock::FAILURE); // (string) 'fail'
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