### Question:
StreamMetadataCache { boolean putStreamProperties(long streamId, StreamProperties props) { return null == streams.putIfAbsent(streamId, props); } StreamMetadataCache(RootRangeClient scClient);   }### Answer:
@Test public void testPutStreamProperties() throws Exception { assertEquals(0, cache.getStreams().size()); assertTrue(cache.putStreamProperties(1234L, props)); assertEquals(1, cache.getStreams().size()); assertFalse(cache.putStreamProperties(1234L, props)); assertEquals(1, cache.getStreams().size()); }