Adapts the existing Fetcher-based MBCAA client to the new Provider
abstraction. mbcaaProvider embeds *Fetcher and implements
Provider + AlbumCoverProvider + TestableProvider. init() registers a
default-config instance; NewMBCAAProviderFromConfig swaps in
production config (User-Agent, MinPeriod) at boot.
Wrapper approach (rather than reimplementing the HTTP logic) keeps
the package compiling during the T4–T8 window: enricher.go and
main.go still reference the legacy Fetcher type / NewFetcher
constructor / Fetch method, all of which remain unchanged in
fetcher.go. A-T8 will consolidate the HTTP logic into this file and
delete fetcher.go after the enricher rewrite removes the last
legacy call sites.
TestConnection hits a hardcoded popular release MBID (Beatles
"Abbey Road" UK release) and treats both 200 and 404 as "connection
works" — MBCAA needs no auth, so only 5xx / network failures
surface. Tests cover ID/DisplayName/Capability metadata, success
path, 404→ErrNotFound, disabled-returns-ErrNotFound, Configure
toggle, TestConnection variants, and NewMBCAAProviderFromConfig
swap.
bvandeusen
1e3a76eba8