@VisibleForTesting
    static void checkSamePrefixedProviders(
            Map<String, DelegationTokenProvider> providers, Set<String> warnings) {
        Set<String> providerPrefixes = new HashSet<>();
        for (String name : providers.keySet()) {
            String[] split = name.split("-");
            if (!providerPrefixes.add(split[0])) {
                String msg =
                        String.format(
                                "Multiple providers loaded with the same prefix: %s. This might lead to unintended consequences, please consider using only one of them.",
                                split[0]);
                warnings.add(msg);
            }
        }
    }
@Test
    public void checkSamePrefixedProvidersShouldNotGiveErrorsWhenNoSamePrefix() {
        Map<String, DelegationTokenProvider> providers = new HashMap<>();
        providers.put("s3-hadoop", new TestDelegationTokenProvider());
        Set<String> warnings = new HashSet<>();
        DefaultDelegationTokenManager.checkSamePrefixedProviders(providers, warnings);
        assertTrue(warnings.isEmpty());
    }