private SchemaNode generateSchemaTree() {
    SchemaNode root = new SchemaInternalNode("root");

    SchemaNode sg = new SchemaInternalNode("sg");
    root.addChild("sg", sg);

    SchemaEntityNode d1 = new SchemaEntityNode("d1");
    sg.addChild("d1", d1);

    MeasurementSchema schema1 = new MeasurementSchema("s1", TSDataType.INT32);
    MeasurementSchema schema2 = new MeasurementSchema("s2", TSDataType.INT64);
    SchemaMeasurementNode s1 = new SchemaMeasurementNode("s1", schema1);
    d1.addChild("s1", s1);
    SchemaMeasurementNode s2 = new SchemaMeasurementNode("s2", schema2);
    s2.setAlias("status");
    d1.addChild("s2", s2);
    d1.addAliasChild("status", s2);

    SchemaEntityNode d2 = new SchemaEntityNode("d2");
    sg.addChild("d2", d2);
    d2.addChild("s1", s1);
    d2.addChild("s2", s2);
    d2.addAliasChild("status", s2);

    SchemaEntityNode a = new SchemaEntityNode("a");
    a.setAligned(true);
    d2.addChild("a", a);
    a.addChild("s1", s1);
    a.addChild("s2", s2);
    a.addAliasChild("status", s2);

    return root;
  }
Generate the following tree: root.sg.d1.s1, root.sg.d1.s2(status) root.sg.d2.s1,
root.sg.d2.s2(status) root.sg.d2.a.s1, root.sg.d2.a.s2(status)

@return the root node of the generated schemTree
iotdb-core/datanode/src/test/java/org/apache/iotdb/db/queryengine/common/schematree/ClusterSchemaTreeTest.java