PHP-Mock: mocking built-in PHP functions
PHP-Mock is a testing library which mocks non deterministic built-in PHP functions like
time()
or rand()
. This is achived by PHP's namespace fallback policy:
PHP will fall back to global functions […] if a namespaced function […] does not exist.
PHP-Mock uses that feature by providing the namespaced function. I.e. you have to be in a non global namespace context and call the function unqualified:
<?php
namespace foo;
$time = time(); // This call can be mocked, a call to \time() can't.
Requirements and restrictions
-
PHP-5.4 or newer. There's also a PHP-5.3 branch.
-
Only unqualified function calls in a namespace context can be mocked. E.g. a call for
time()
in the namespacefoo
is mockable, a call for\time()
is not. -
The mock has to be defined before the first call to the unqualified function in the tested class. This is documented in Bug #68541. In most cases you can ignore this restriction. But if you happen to run into this issue you can call
Mock::define()
before that first call. This would define a side effectless namespaced function which can be enabled later.
Alternatives
If you can't rely on or just don't want to use the namespace fallback policy, there are alternative techniques to mock built-in PHP functions:
-
PHPBuiltinMock relies on the APD extension.
-
MockFunction is a PHPUnit extension. It uses the runkit extension.
-
UOPZ is a Zend extension which allows, among others, renaming and deletion of functions.
-
vfsStream is a stream wrapper for a virtual file system. This will help you write tests which covers PHP stream functions (e.g.
fread()
orreaddir()
).
Installation
Use Composer:
{
"require-dev": {
"php-mock/php-mock": "^0.7"
}
}
Usage
You don't need to learn yet another API. PHP-Mock has integrations for these testing frameworks:
-
php-mock/php-mock-phpunit - PHPUnit integration
-
php-mock/php-mock-mockery - Mockery integration
PHP-Mock API
You find the API in the namespace
phpmock
.
Create a Mock
object. You can do this with the fluent API of MockBuilder
:
-
MockBuilder::setNamespace()
sets the target namespace of the mocked function. -
MockBuilder::setName()
sets the name of the mocked function (e.g.time()
). -
MockBuilder::setFunction()
sets the concrete mock implementation. -
MockBuilder::setFunctionProvider()
sets alternativly toMockBuilder::setFunction()
the mock implementation as aFunctionProvider
:-
FixedValueFunction
is a simple implementation which returns always the same value. -
FixedMicrotimeFunction
is a simple implementation which returns always the same microtime. This class is different toFixedValueFunction
as it contains a converter formicrotime()
's float and string format. -
FixedDateFunction
is a simple implementation which returns always a formated date for the fixed timestamp. -
SleepFunction
is asleep()
implementation, which doesn't halt but increases anIncrementable
e.g. atime()
mock. -
UsleepFunction
is anusleep()
implementation, which doesn't halt but increases anIncrementable
e.g. amicrotime()
mock.
-
-
MockBuilder::build()
builds aMock
object.
After you have build your Mock
object you have to call enable()
to enable the mock in the given namespace. When you are finished with that mock you
should disable it by calling disable()
on the mock instance.
This example illustrates mocking of the unqualified function time()
in the
namespace foo
:
<?php
namespace foo;
use phpmock\MockBuilder;
$builder = new MockBuilder();
$builder->setNamespace(__NAMESPACE__)
->setName("time")
->setFunction(
function () {
return 1417011228;
}
);
$mock = $builder->build();
// The mock is not enabled yet.
assert (time() != 1417011228);
$mock->enable();
assert (time() == 1417011228);
// The mock is disabled and PHP's built-in time() is called.
$mock->disable();
assert (time() != 1417011228);
Instead of setting the mock function with MockBuilder::setFunction()
you could also
use the existing FixedValueFunction
:
<?php
namespace foo;
use phpmock\MockBuilder;
use phpmock\functions\FixedValueFunction;
$builder = new MockBuilder();
$builder->setNamespace(__NAMESPACE__)
->setName("time")
->setFunctionProvider(new FixedValueFunction(1417011228));
$mock = $builder->build();
Mock environments
Complex mock environments of several mocked functions can be grouped in a MockEnvironment
:
-
MockEnvironment::enable()
enables all mocked functions of this environment. -
MockEnvironment::disable()
disables all mocked functions of this environment.
SleepEnvironmentBuilder
The SleepEnvironmentBuilder
builds a mock environment where sleep()
and usleep()
return immediatly.
Furthermore they increase the amount of time in the mocked date()
, time()
and
microtime()
:
<?php
namespace foo;
use phpmock\SleepEnvironmentBuilder;
$builder = new SleepEnvironmentBuilder();
$builder->setNamespace(__NAMESPACE__)
->setTimestamp(1417011228);
$environment = $builder->build();
$environment->enable();
// This won't delay the test for 10 seconds, but increase time().
sleep(10);
assert(1417011228 + 10 == time());
Reset global state
An enabled mock changes global state. This will break subsequent tests if
they run code which would call the mock unintentionally. Therefore
you should always disable a mock after the test case. You will have to disable
the created mock. You could do this for all mocks by calling the
static method
Mock::disableAll()
.
License and authors
This project is free and under the WTFPL. Responsable for this project is Markus Malkusch markus@malkusch.de. This library was inspired by Fabian Schmengler's article PHP: “Mocking” built-in functions like time() in Unit Tests.
Donations
If you like PHP-Mock and feel generous donate a few Bitcoins here: 1335STSwu9hST4vcMRppEPgENMHD2r1REK