@Test
    public void testInt8VectorInvalidHex() {
        var type = TensorType.fromSpec("tensor<int8>(x[2])");
        String denseJson = "{\"values\":\"abXc\"}";
        try {
            Tensor decoded = JsonFormat.decode(type, denseJson.getBytes(StandardCharsets.UTF_8));
            fail("did not get exception as expected, decoded as: "+decoded);
        } catch (IllegalArgumentException e) {
            assertEquals(e.getMessage(), "Invalid digit 'X' at index 2 in input abXc");
        }
    }
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