@Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        QueryEntry that = (QueryEntry) o;
        if (!key.equals(that.key)) {
            return false;
        }
        return true;
    }
@Test(expected = NullPointerException.class)
    @SuppressWarnings("ResultOfMethodCallIgnored")
    public void test_equality_empty() {
        QueryableEntry entryKeyLeft = createEntry();
        QueryableEntry entryKeyRight = createEntry();

        entryKeyLeft.equals(entryKeyRight);
    }