We define two beans returning Fooable inside ExampleConfiguration. The beans are essentially mutually exclusive, since "noop" relies on a prop while "default" relies on no other available bean.

Points of interest

1. ExampleConfiguration#fooableValue's parameter fooable complains that it doesn't know which bean is going to get injected.
2. DefaultFooableTests's @Autowired fooable complains that it doesn't know which bean is going to get injected.
3. NoopFooableTests's @Autowired fooable complains that it doesn't know which bean is going to get injected.

In order to showcase that the configuration actually works and correctly returns only one bean for each case, I've written two tests.