@Test
    public void tensor_add_update_on_sparse_tensor() {
        assertTensorAddUpdate("{{x:a,y:b}:2.0, {x:c,y:d}: 3.0}", "sparse_tensor",
                              """
                              {
                                "cells": [
                                  { "address": { "x": "a", "y": "b" }, "value": 2.0 },
                                  { "address": { "x": "c", "y": "d" }, "value": 3.0 }
                                ]
                              }""");
    }
Tests parsing of various tensor values set at the root, i.e. no 'cells', 'blocks' or 'values'
document/src/test/java/com/yahoo/document/json/JsonReaderTestCase.java