message: update metrics' test
diff: package org.hyperledger.indy.sdk.metrics;
  import org.hyperledger.indy.sdk.IndyIntegrationTest;
  +import org.json.JSONObject;
  import org.junit.Test;
  +
  +import java.math.BigInteger;
  +import java.util.Map;
  import static org.junit.Assert.assertNotNull;
  @@ -9,8 +13,11 @@ public class CollectMetricsTest extends IndyIntegrationTest {
  @Test
  public void testCollectMetricsMethod() throws Exception {
  - String metrics_map = Metrics.collectMetrics().get();
  - assertNotNull(metrics_map);
  -
  + String metricsResult = Metrics.collectMetrics().get();
  + assertNotNull(metricsResult);
  + Map<String, Object> metricMap = (new JSONObject(metricsResult)).toMap();
  + assert(metricMap.containsKey("threadpool_active_count"));
  + // check that vales from the result can be parsed to BigIntegers
  + metricMap.values().forEach(v-> new BigInteger(String.valueOf(v)));
  }
  }
  