diff --git a/tests/functional/lang/eval-okay-substring.exp b/tests/functional2/lang/builtins.substring/eval-okay-2.out.exp
similarity index 100%
rename from tests/functional/lang/eval-okay-substring.exp
rename to tests/functional2/lang/builtins.substring/eval-okay-2.out.exp
diff --git a/tests/functional/lang/eval-okay-substring-context.exp b/tests/functional2/lang/builtins.substring/eval-okay-context.out.exp
similarity index 100%
rename from tests/functional/lang/eval-okay-substring-context.exp
rename to tests/functional2/lang/builtins.substring/eval-okay-context.out.exp
diff --git a/tests/functional/lang/eval-okay-substring.nix b/tests/functional2/lang/builtins.substring/in-2.nix
similarity index 100%
rename from tests/functional/lang/eval-okay-substring.nix
rename to tests/functional2/lang/builtins.substring/in-2.nix
diff --git a/tests/functional/lang/eval-okay-substring-context.nix b/tests/functional2/lang/builtins.substring/in-context.nix
similarity index 100%
rename from tests/functional/lang/eval-okay-substring-context.nix
rename to tests/functional2/lang/builtins.substring/in-context.nix