[TEST] improve ClusterStatsIT to better check mem values returned

Rather than checking that those values are greater than 0, we can sum up the values gotten from all nodes and check that what is returned is that same value.

core/src/main/java/org/elasticsearch/monitor/os/OsStats.java

@@ -265,7 +265,7 @@ public class OsStats implements Writeable, ToXContent {
         }
     }
 
-    private static short calculatePercentage(long used, long max) {
+    public static short calculatePercentage(long used, long max) {
         return max <= 0 ? 0 : (short) (Math.round((100d * used) / max));
     }
 }

core/src/test/java/org/elasticsearch/action/admin/cluster/stats/ClusterStatsIT.java

@@ -21,12 +21,15 @@ package org.elasticsearch.action.admin.cluster.stats;
 
 import org.elasticsearch.Version;
 import org.elasticsearch.action.admin.cluster.health.ClusterHealthResponse;
+import org.elasticsearch.action.admin.cluster.node.stats.NodeStats;
+import org.elasticsearch.action.admin.cluster.node.stats.NodesStatsResponse;
 import org.elasticsearch.client.Requests;
 import org.elasticsearch.cluster.health.ClusterHealthStatus;
 import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.common.Priority;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.util.concurrent.EsExecutors;
+import org.elasticsearch.monitor.os.OsStats;
 import org.elasticsearch.node.Node;
 import org.elasticsearch.test.ESIntegTestCase;
 import org.elasticsearch.test.ESIntegTestCase.ClusterScope;
@@ -181,12 +184,20 @@ public class ClusterStatsIT extends ESIntegTestCase {
         assertThat(msg, response.nodesStats.getProcess().getMinOpenFileDescriptors(), Matchers.greaterThanOrEqualTo(-1L));
         assertThat(msg, response.nodesStats.getProcess().getMaxOpenFileDescriptors(), Matchers.greaterThanOrEqualTo(-1L));
 
-        assertThat(msg, response.nodesStats.getOs().getMem().getFree().bytes(), Matchers.greaterThanOrEqualTo(0L));
-        assertThat(msg, response.nodesStats.getOs().getMem().getTotal().bytes(), Matchers.greaterThanOrEqualTo(0L));
-        assertThat(msg, response.nodesStats.getOs().getMem().getUsed().bytes(), Matchers.greaterThanOrEqualTo(0L));
-        assertThat(msg, response.nodesStats.getOs().getMem().getUsedPercent(), Matchers.greaterThanOrEqualTo((short)0));
-        assertThat(msg, response.nodesStats.getOs().getMem().getFreePercent(), Matchers.greaterThanOrEqualTo((short)0));
-
+        NodesStatsResponse nodesStatsResponse = client().admin().cluster().prepareNodesStats().setOs(true).get();
+        long total = 0;
+        long free = 0;
+        long used = 0;
+        for (NodeStats nodeStats : nodesStatsResponse.getNodes()) {
+            total += nodeStats.getOs().getMem().getTotal().bytes();
+            free += nodeStats.getOs().getMem().getFree().bytes();
+            used += nodeStats.getOs().getMem().getUsed().bytes();
+        }
+        assertEquals(msg, free, response.nodesStats.getOs().getMem().getFree().bytes());
+        assertEquals(msg, total, response.nodesStats.getOs().getMem().getTotal().bytes());
+        assertEquals(msg, used, response.nodesStats.getOs().getMem().getUsed().bytes());
+        assertEquals(msg, OsStats.calculatePercentage(used, total), response.nodesStats.getOs().getMem().getUsedPercent());
+        assertEquals(msg, OsStats.calculatePercentage(free, total), response.nodesStats.getOs().getMem().getFreePercent());
     }
 
     public void testAllocatedProcessors() throws Exception {