This commit reviews how bean override support can influence the key of
an application context cached by the TCF. OverrideMetadata and its
subclasses now implement a proper equals/hashCode pair that is tested
in various scenarios.
Due to how the TCF operates, OverrideMetadata has to be computed in
two locations:
1. In a ContextCustomizerFactory, using the metadata in the enclosing
class if any. This determines whether a customizer is needed in the
first place. The computed set of unique metadata identifies the
customizer and participates in the application context cache's key.
2. In the TestExecutionListener so that it knows the override points
it has to process.
Parsing of the metadata based on a test class has been greatly
simplified and moved to OverrideMetadata proper as we don't need several
flavors. 1 and 2 are using the same algorithm with the former wrapping
that in a Set to compute a proper key.
BeanOverrideContextCustomizerEqualityTests provides a framework for
testing edge cases as we only care about whether the created
ContextCustomizer behaves correctly against the identity of another.
Closes gh-32884
Stéphane Nicoll
7916f74942