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Subject: Re: [PHP-DEV] [Discussion] Sandbox API
In-Reply-To: <e08f6af322dcc5b4e4dd5e772f28be07ffa07ba4.camel@ageofdream.com>
Date: Tue, 6 Aug 2024 04:57:39 -0400
Cc: PHP internals <internals@lists.php.net>
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Message-ID: <95EDE362-6618-401F-8CD9-2D7C2F05B205@newclarity.net>
References: <e08f6af322dcc5b4e4dd5e772f28be07ffa07ba4.camel@ageofdream.com>
To: Nick Lockheart <lists@ageofdream.com>
From: mike@newclarity.net (Mike Schinkel)

> On Aug 6, 2024, at 2:09 AM, Nick Lockheart <lists@ageofdream.com> =
wrote:
>=20
> Sand Box: A first class API that allows unit testing of code with =
mocks
> and stubs of other classes or functions, without the need to modify =
the
> class under test.
>=20
> This is an initial idea of how a Sand Box API could work:
>=20
> $oSandbox =3D new SPLSandBox();
>=20
> $oSandbox->MockFunction('\mocks\fopen','\fopen');
> $oSandbox->MockFunction('\mocks\fread','\fread');
> $oSandbox->MockFunction('\mocks\fwrite','\fwrite');
> $oSandbox->MockFunction('\mocks\fclose','\fclose');
>=20
> $oFileManager =3D $oSandbox->GetInstance('MyFileManager');
>=20
> $oFileManager->WriteFile('/path/to/file.txt');

On the surface, this sounds like a good idea.

This is already possible to do in userland, with a few edge-cases. The =
edge-cases are:

1. Anything that uses `self::class` or similar will break if it expects =
`MyFileManager` to be returned instead of something like =
`MyFileManager_4k2x8j`.

2. Anything that expects a static variable in `MyFileManager` to have a =
pre-existing value set but an earlier use of `MyFileManager` will not =
work as expected. However, expecting that would be against testing best =
practices so I don't see this as a real concern given your use-case.

OTOH, a userland implementation will also not be very performant when =
compared to a potential PHP core implementation, making it less than =
ideal for testing.=20

However, doing a userland implementation would be a good =
proof-of-concept, allow others to try it, allow others to contribute to =
the exact syntax and semantics, and finally a userland implementation =
could reveal any potential hidden issues in the design before moving on =
to a proper implementation in C for PHP core.

-Mike

P.S. If you are unfamiliar with how to implement in userland you can use =
the same techniques I used in my proof-of-concept for Userland Packages: =
 https://github.com/mikeschinkel/userland-packages. If that link is not =
enough and you instead want to ask specific questions about how to =
implement in PHP, feel free to contact me off-list.