General notes on usage

[uuf6429]

First of all, I went for this package because the gillion other vfs composer packages seem to be unmaintained or not very mature.

I got the feeling that this library mixes up global/static scope with instances a bit.
For example, looking at the provided sample, I thought vfsStream::setup() would return a vfsStream object, not a vfsDirectory.
After looking at the code, it became obvious: in reality there is only one stream wrapper being registered.

Also, storing the created vfsDirectory instance in a (private) property causes an IDE warning that it seems to not be used (only written once). While it's not a problem, the warning does kinda make sense - there are many ways in PHP to avoid an early deconstruction/dereferencing of objects.

While static classes might be handier to work with, they do encourage the habit of writing bad code - so I'd recommend a singleton approach is a bit better than static. This approach might also open up the possibility of multiple isolated vfs wrappers.

Here's what I imagine it to look like:

class MyClassTest extends TestCase
{
    public function testThatSomethingWorks(): void
    {
        $vfs = VfsStream::setUp();
        $sut = new MyClass($vfs());     // $vfs() is just a shortcut for url() - since I find that url is an implementation
                                        // detail of vfs. There are probably more idiomatic alternatives, like ->get() or so,
                                        // whereas the __invoke approach is just a handy shortcut.

        $sut->doSomething();

        $this->assertFileExists($vfs('file-created-by-myclass.txt'));
    }

    public function testThatMultipleVfsWorks(): void
    {
        $vfs1 = VfsStream::setUp();
        $vfs2 = VfsStream::setUp();
        file_put_contents($vfs1('test.txt'), 'hello world');

        rename($vfs1('test.txt'), $vfs2('test2.txt'));

        $this->assertFileDoesNotExist($vfs1('test.txt'));
        $this->assertFileExists($vfs2('test2.txt'));
    }

This is just my two cents, library is already totally usable as it is.