private void doValueAsserts(final Optional<String> optFoundValue,
                                final long expectedStreamId,
                                final String expectedMapName,
                                final String expectedValuePart) {
        assertThat(optFoundValue)
                .isNotEmpty();
        String[] parts = optFoundValue.get()
                .split("\\|");
        assertThat(parts)
                .hasSize(4);
        assertThat(Long.parseLong(parts[1]))
                .isEqualTo(expectedStreamId);
        assertThat(parts[2])
                .isEqualTo(expectedMapName);
        assertThat(parts[3])
                .isEqualTo(expectedValuePart);
    }
Make sure that it copes with a map not being in an early stream but is in a later one.
stroom-app/src/test/java/stroom/pipeline/refdata/TestReferenceData.java