Force reload of entity metadatas

Nobody has claimed this yet.

I have extended `WebTestCase` and implemented my tests the same as usual. However when running 'all' tests as a batch I came across a problem.

The code I'm testing uses a custom metadata driver. This drivers `getAllClassNames` method will return a subset of the defined entities depending on the bundles configuration. In practice, this works perfectly, in testing it does not. I've tracked the problem down to `WebTestCase::loadFixtures`, which loads the metadatas and stores them in a `private static array`. This means I cannot change which metadatas are loaded once the tests have started.

The easiest fix for this would be to declare `WebTestCase::$cachedMetadatas` as `protected`, that way I can reset it from my derived class.

Can anybody suggest a way around this problem?

Start by reading WebTestCase::loadFixtures and the private static cachedMetadatas property to understand when metadata is loaded and reused. Reproduce the issue with a custom metadata driver while running the full test batch, then verify that metadata can be refreshed or reset between differing bundle configurations.

Written by the indexing model from the issue text.