Enhance NixOS tests by adding a wait for PostgreSQL setup completion and verifying the existence of the 'webref' database role. This improves the reliability of database accessibility checks in the testing process.

nixos/tests.nix

@@ -176,6 +176,14 @@
       start_all()
       machine.wait_for_unit("postgresql.service")
       
+      # Wait for PostgreSQL setup scripts to complete (database and user creation)
+      import time
+      machine.wait_for_unit("postgresql-setup.service", timeout=30)
+      time.sleep(2)  # Give it a moment to finalize
+      
+      # Verify database role exists
+      machine.succeed("sudo -u postgres psql -c '\\du' | grep webref")
+      
       # Verify database is accessible with webref user
       machine.succeed("sudo -u webref psql webref -c 'SELECT 1;'")