Tests for FeaturesManager::assignInterPackageDependencies()

Thanks for the patch. And with a draft test too :)

+++ b/src/FeaturesManager.php
@@ -633,7 +633,7 @@ class FeaturesManager implements FeaturesManagerInterface {
+                $this->mergeUniqueItems($package['dependencies'], [$this->getAssigner()->getBundle()->getFullName($config_collection[$dependency_name]['name'])]);

'machine_name' is indeed incorrect. The dependency is on an existing exported feature, so the key we need here is 'package' (which tracks the package that provides the given piece of configuration) rather than 'name' (the name of the configuration item). For a bit more on what the config collection item keys represent, see the documentation to FeaturesManagerInterface::getConfigCollection().

I know the code is very hard to follow. We're trying to improve that in #2606926: Error "The following module is missing from the file system", #2595263: Remodel packages as objects, #2595265: Remodel configuration items in FeaturesManager::configCollection as objects, and #2569149: Use ConfigEntity for features bundles. Meanwhile, welcome to Features 3.x and thanks for helping fix things up!

Because I had to rewrite the section of code with this bug, I ended up including a fix in #2606926: Error "The following module is missing from the file system" (see patch).

I'd love get the test in though, particularly because it helps model how we can write similar tests. Here's a redraft.

This is slightly closer but not yet completing for me locally.

This should pass, but only because I've removed an argument to FeaturesAssigner::getBundle(), suggesting a bug there.

@dawehner: committed. This helps model what we need to do in other unit tests. Thanks for the guidance!