https://github.com/spring-projects/spring-boot/issues/26022 has introduced additional integration tests that configure a number of repositories for each test, for example:
https://github.com/spring-projects/spring-boot/blob/c63eba32f95779f343612f36e4cd0c68efb37e42/spring-boot-tests/spring-boot-integration-tests/spring-boot-sni-tests/spring-boot-sni-client-app/settings.gradle#L2-L7
Unfortunately this doesn't match the repositories that the build configures, typically for commercial releases.