[testing] Formatter cache is not cleared after tests

[imorland]

Current Behavior

When running tests which involve the Formatter, the formatter cache is not cleared at the end of the test run

Steps to Reproduce

• Run a test which does not enable flarum/markdown
• Write a test which enabled flarum/markdown
• test the output
• run both tests again, notice that the previous first test now fails

By adding

protected function tearDown(): void
    {
        parent::tearDown();

        resolve(Formatter::class)->flush();
    }

To the test class, behaviour is as would be expected.

Expected Behavior

The Formatter cache should be cleared as part of tearDown()

Screenshots

No response

Environment

• Flarum version: x.y.z
• Website URL: http://example.com
• Webserver: [e.g. apache, nginx]
• Hosting environment: [e.g. shared, vps]
• PHP version: x.y.z
• Browser: [e.g. chrome 67, safari 11]

Output of php flarum info

Output of "php flarum info", run this in terminal in your Flarum directory.

Possible Solution

No response

Additional Context

No response

[n-peugnet]

Similarly to this, the application's cache is not cleared between each tests, this took me quite some time to realize while trying to write some tests for code that interact with the cache.

I solved it by clearing the cache myself in the tearDown() using this line:

$this->app()->getContainer()->make(\Illuminate\Contracts\Cache\Store::class)->flush();

But IMO this should be always done, as the tests should be as independent from each other as possible.

[SychO9]

PR welcome :)