An incomplete shard snapshot will prevent a shard from moving away from a node (see `SnapshotInProgressAllocationDecider`). That means that when a shard snapshot completes it may become possible to perform some shard movements that previously were not possible, so we should trigger a reroute to start those movements. AFAICT we do not trigger such a reroute today.
test/framework/src/main/java/org/elasticsearch/test/ESTestCase.java
boolean terminated = true;
        for (ExecutorService service : services) {
            if (service != null) {
                terminated &= ThreadPool.terminate(service, 10, TimeUnit.SECONDS);
            }
        }
        return terminated;
    }
    public static boolean terminate(ThreadPool threadPool) {
        return ThreadPool.terminate(threadPool, 10, TimeUnit.SECONDS);
    }
    /**
     * Returns a {@link java.nio.file.Path} pointing to the class path relative resource given
     * as the first argument. In contrast to
     * <code>getClass().getResource(...).getFile()</code> this method will not
     * return URL encoded paths if the parent path contains spaces or other
     * non-standard characters.
     */
    @Override
    public Path getDataPath(String relativePath) {
        
        
        
        try {
            return PathUtils.get(getClass().getResource(relativePath).toURI()).toAbsolutePath().normalize();
        } catch (Exception e) {
            throw new RuntimeException("resource not found: " + relativePath, e);
        }
    }