YARN-11267. Fix Junit Test Error.

Author: slfan1989

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-router/src/main/java/org/apache/hadoop/yarn/server/router/webapp/FederationInterceptorREST.java

@@ -1002,7 +1002,7 @@ private SubClusterInfo getNodeSubcluster(String nodeId) throws NotFoundException
     NodeInfo nodeInfo = null;
     for (Entry<SubClusterInfo, NodeInfo> entry : results.entrySet()) {
       NodeInfo nodeResponse = entry.getValue();
-      if (nodeInfo == null || (nodeInfo != null && nodeResponse != null &&
+      if (nodeInfo == null || (nodeResponse != null &&
          nodeInfo.getLastHealthUpdate() < nodeResponse.getLastHealthUpdate())) {
         subcluster = entry.getKey();
         nodeInfo = nodeResponse;
@@ -3405,6 +3405,10 @@ private <R> Map<SubClusterInfo, R> invokeConcurrent(Collection<SubClusterInfo> c
     }
 
     if (results.isEmpty() && lastException != null) {
+      Throwable cause = lastException.getCause();
+      if (cause != null) {
+        throw new YarnRuntimeException(cause.getMessage());
+      }
       throw new YarnRuntimeException(lastException.getMessage());
     }
     return results;

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-router/src/test/java/org/apache/hadoop/yarn/server/router/webapp/TestFederationInterceptorRESTRetry.java

@@ -556,8 +556,10 @@ public void testGetNodesOneBadSCAllowPartial() throws Exception {
     interceptor.setAllowPartialResult(true);
     setupCluster(Arrays.asList(bad2));
 
-    NodesInfo nodesInfo = interceptor.getNodes(null);
-    assertNotNull(nodesInfo);
+    YarnRuntimeException exception = assertThrows(YarnRuntimeException.class, () -> {
+      interceptor.getNodes(null);
+    });
+    assertTrue(exception.getMessage().contains("RM is stopped"));
 
     // We need to set allowPartialResult=false
     interceptor.setAllowPartialResult(false);
@@ -572,8 +574,10 @@ public void testGetNodesTwoBadSCsAllowPartial() throws Exception {
     interceptor.setAllowPartialResult(true);
     setupCluster(Arrays.asList(bad1, bad2));
 
-    NodesInfo nodesInfo = interceptor.getNodes(null);
-    assertNotNull(nodesInfo);
+    YarnRuntimeException exception = assertThrows(YarnRuntimeException.class, () -> {
+      interceptor.getNodes(null);
+    });
+    assertTrue(exception.getMessage().contains("RM is stopped"));
 
     // We need to set allowPartialResult=false
     interceptor.setAllowPartialResult(false);