source: class CtrlPhysicalStorageApiCallHandlerTest {
  
      @Test
      public void testGroupLsBlkEntriesByNode() throws InvalidNameException
      {
  
target:         Map<NodeName, List<LsBlkEntry>> testData = new HashMap<>();
          final NodeName alpha = new NodeName("alpha");
          final NodeName bravo = new NodeName("bravo");
          final NodeName charlie = new NodeName("charlie");
  
          List<LsBlkEntry> data = new ArrayList<>();
          data.add(
              new LsBlkEntry(
                  "sde",
                  512L*1024*1024*1024,
                  false,
                  "",
                  "sde",
                  "",
                  8,
                  9,
                  "",
                  "",
                  ""
              )
          );
  
          testData.put(alpha, data);
  
          testData.put(bravo, data);
  
          List<LsBlkEntry> dataCharlie = new ArrayList<>();
          dataCharlie.add(
              new LsBlkEntry(
                  "sde",
                  512L*1024*1024*1024,
                  false,
                  "",
                  "sde",
                  "",
                  8,
                  9,
                  "",
                  "",
                  ""
              )
          );
          dataCharlie.add(
              new LsBlkEntry(
                  "sdd",
                  640L*1024*1024*1024,
                  true,
                  "",
                  "sdd",
                  "",
                  9,
                  0,
                  "",
                  "",
                  ""
              )
          );
          dataCharlie.add(
              new LsBlkEntry(
                  "sdf",
                  512L*1024*1024*1024,
                  true,
                  "",
                  "sdf",
                  "",
                  9,
                  10,
                  "",
                  "",
                  ""
              )
          );
  
          testData.put(charlie, dataCharlie);
  
          final List<JsonGenTypes.PhysicalStorage> physicalStorages =
              CtrlPhysicalStorageApiCallHandler.groupPhysicalStorageByDevice(testData);
  
          Assert.assertEquals(3, physicalStorages.size());
          Assert.assertEquals(3, physicalStorages.get(0).nodes.size());
          Assert.assertEquals(1, physicalStorages.get(1).nodes.size());
          Assert.assertEquals(1, physicalStorages.get(2).nodes.size());
          Assert.assertTrue(physicalStorages.get(1).nodes.containsKey("charlie"));
          Assert.assertEquals("sdf", physicalStorages.get(1).nodes.get("charlie").get(0).device);
      }
  
  }