@Test
    public void testSingleSparseDimensionShortForm() {
        Tensor.Builder builder = Tensor.Builder.of(TensorType.fromSpec("tensor(x{})"));
        builder.cell().label("x", "a").value(2.0);
        builder.cell().label("x", "c").value(3.0);
        Tensor expected = builder.build();

        String json= "{\"cells\":{" +
                     "\"a\":2.0," +
                     "\"c\":3.0" +
                     "}}";
        Tensor decoded = JsonFormat.decode(expected.type(), json.getBytes(StandardCharsets.UTF_8));
        assertEquals(expected, decoded);
    }
Tests parsing of various tensor values set at the root, i.e. no 'cells', 'blocks' or 'values'
vespajlib/src/test/java/com/yahoo/tensor/serialization/JsonFormatTestCase.java