Handle system test derivations in create-small-backup

Otherwise this table is empty.

scripts/guix-data-service-create-small-backup

@@ -62,6 +62,17 @@ WHERE revision_id IN (
   )
 );
 
+CREATE UNLOGGED TABLE tmp_guix_revision_system_test_derivations AS
+SELECT *
+FROM guix_revision_system_test_derivations
+WHERE guix_revision_id IN (
+  SELECT id
+  FROM guix_revisions
+  WHERE commit IN (
+    SELECT commit FROM git_branches
+  )
+);
+
 CREATE UNLOGGED TABLE tmp_package_derivations AS
 SELECT * FROM package_derivations WHERE id IN (
   SELECT package_derivation_id FROM tmp_guix_revision_package_derivations
@@ -69,7 +80,12 @@ SELECT * FROM package_derivations WHERE id IN (
 
 CREATE UNLOGGED TABLE tmp_derivations AS
 WITH RECURSIVE derivation_ids(id) AS (
-    SELECT derivation_id FROM tmp_package_derivations
+    (
+        SELECT tmp_package_derivations.derivation_id FROM tmp_package_derivations
+      UNION
+        SELECT tmp_guix_revision_system_test_derivations.derivation_id
+        FROM tmp_guix_revision_system_test_derivations
+    )
   UNION
     SELECT derivation_outputs.derivation_id
     FROM derivation_ids
@@ -209,6 +225,9 @@ INSERT INTO package_derivations OVERRIDING SYSTEM VALUE
 INSERT INTO guix_revision_package_derivations
   SELECT * FROM tmp_guix_revision_package_derivations;
 
+INSERT INTO guix_revision_system_test_derivations
+  SELECT * FROM tmp_guix_revision_system_test_derivations;
+
 INSERT INTO builds OVERRIDING SYSTEM VALUE
   SELECT * FROM tmp_builds;