-- Test rdf_fdw_version() returns a non-empty string
SELECT length(rdf_fdw_version()) > 0 AS version_exists;
 version_exists 
----------------
 t
(1 row)

-- Test rdf_fdw_version() contains expected components
SELECT 
    rdf_fdw_version() ~ 'rdf_fdw\s+[0-9]+\.[0-9]+' AS has_rdf_fdw_version,
    rdf_fdw_version() ~ 'PostgreSQL\s+[0-9]+' AS has_postgresql_version,
    rdf_fdw_version() ~ 'libxml\s+[0-9]+\.[0-9]+' AS has_libxml_version,
    rdf_fdw_version() ~ 'librdf\s+[0-9]+\.[0-9]+' AS has_librdf_version,
    rdf_fdw_version() ~ 'libcurl\s+[0-9]+\.[0-9]+' AS has_libcurl_version;
 has_rdf_fdw_version | has_postgresql_version | has_libxml_version | has_librdf_version | has_libcurl_version 
---------------------+------------------------+--------------------+--------------------+---------------------
 t                   | t                      | t                  | t                  | t
(1 row)

-- Test rdf_fdw_settings() C function returns a non-empty string
SELECT length(rdf_fdw_settings()) > 0 AS settings_exists;
 settings_exists 
-----------------
 t
(1 row)

-- Test rdf_fdw_settings() C function contains expected core components
SELECT 
    rdf_fdw_settings() ~ 'rdf_fdw\s+[0-9]+\.[0-9]+' AS has_rdf_fdw,
    rdf_fdw_settings() ~ 'PostgreSQL\s+[0-9]+' AS has_postgresql,
    rdf_fdw_settings() ~ 'libxml\s+[0-9]+\.[0-9]+' AS has_libxml,
    rdf_fdw_settings() ~ 'librdf\s+[0-9]+\.[0-9]+' AS has_librdf,
    rdf_fdw_settings() ~ 'libcurl\s+[0-9]+\.[0-9]+' AS has_libcurl;
 has_rdf_fdw | has_postgresql | has_libxml | has_librdf | has_libcurl 
-------------+----------------+------------+------------+-------------
 t           | t              | t          | t          | t
(1 row)

-- Test rdf_fdw_settings view returns expected components
SELECT component, version IS NOT NULL AS has_version
FROM rdf_fdw_settings
ORDER BY component COLLATE "C" DESC;
 component  | has_version 
------------+-------------
 zlib       | t
 ssl        | t
 rdf_fdw    | t
 nghttp2    | t
 libxml     | t
 librdf     | t
 libcurl    | t
 libSSH     | t
 compiler   | t
 built      | t
 PostgreSQL | t
(11 rows)

-- Test that rdf_fdw_settings view returns core components
SELECT 
    COUNT(*) >= 5 AS has_minimum_components,
    COUNT(*) FILTER (WHERE component = 'rdf_fdw') = 1 AS has_rdf_fdw,
    COUNT(*) FILTER (WHERE component = 'PostgreSQL') = 1 AS has_postgresql,
    COUNT(*) FILTER (WHERE component = 'libxml') = 1 AS has_libxml,
    COUNT(*) FILTER (WHERE component = 'librdf') = 1 AS has_librdf,
    COUNT(*) FILTER (WHERE component = 'libcurl') = 1 AS has_libcurl
FROM rdf_fdw_settings;
 has_minimum_components | has_rdf_fdw | has_postgresql | has_libxml | has_librdf | has_libcurl 
------------------------+-------------+----------------+------------+------------+-------------
 t                      | t           | t              | t          | t          | t
(1 row)