### Question:
ConfigMetadataClient { @Nullable String getLastFetchETag() { return frcMetadata.getString(LAST_FETCH_ETAG_KEY, null); } ConfigMetadataClient(SharedPreferences frcMetadata); boolean isDeveloperModeEnabled(); long getFetchTimeoutInSeconds(); long getMinimumFetchIntervalInSeconds(); FirebaseRemoteConfigInfo getInfo(); @WorkerThread void clear(); @WorkerThread void setConfigSettings(FirebaseRemoteConfigSettings settings); void setConfigSettingsWithoutWaitingOnDiskWrite(FirebaseRemoteConfigSettings settings); @VisibleForTesting static final long LAST_FETCH_TIME_IN_MILLIS_NO_FETCH_YET; }### Answer:
@Test public void getLastFetchETag_isNotSet_returnsEmptyString() { assertThat(metadataClient.getLastFetchETag()).isNull(); }