public static ValAssertion valAsString(final String expected) {
        return (Val out) ->
                Assertions.assertThat(out.toString())
                        .isEqualTo(expected);
    }
No type checking, just that {@link Val#toString()} is equal to expected.
stroom-query/stroom-query-language/src/test/java/stroom/query/language/functions/ValAssertions.java