public static Slime jsonToSlimeOrThrow(String json) {
        return jsonToSlimeOrThrow(json.getBytes(StandardCharsets.UTF_8));
    }
@Test
    public void test_invalid_json() {
        try {
            SlimeUtils.jsonToSlimeOrThrow("foo");
            fail();
        } catch (RuntimeException e) {
            assertEquals("Unexpected character 'o'", e.getMessage());
        }
    }