diff --git a/goodwe_controller/test_safety118.py b/goodwe_controller/test_safety118.py
index f6fe602..e9cb1a9 100644
--- a/goodwe_controller/test_safety118.py
+++ b/goodwe_controller/test_safety118.py
@@ -17,7 +17,6 @@ Mutating a module this file grades? Read MUTATION.md first (purge __pycache__).
 
 import asyncio
 import logging
-from pathlib import Path
 
 import os  # noqa: E402
 import sys  # noqa: E402
@@ -371,7 +370,8 @@ check("pv.unit_fault: None for a good unit and for a missing reading (has_readin
       pv.unit_fault(st(1, "kW")) is None and pv.unit_fault(None) is None
       and pv.unit_fault(st("unavailable")) is None
       and pv.unit_fault(st(1)) == "" and pv.unit_fault(st(1, "kWh")) == "kWh")
-src = (Path(__file__).parent / "app" / "main.py").read_text(encoding="utf-8")
+# MAINT-21: main.py and the files split from it (the forecast read is in ctl_inputs).
+src = main_files.source()
 check("the size rule is gone from main.py", "abs(raw) < 50" not in src)
 
 print()
diff --git a/goodwe_controller/test_validate.py b/goodwe_controller/test_validate.py
index ea9c5df..6cfff7c 100644
--- a/goodwe_controller/test_validate.py
+++ b/goodwe_controller/test_validate.py
@@ -1028,6 +1028,11 @@ check("...and the drain SET is not clamped either, so the twin key the card "
 _srcs = {name: open(os.path.join(os.path.dirname(os.path.abspath(__file__)),
                                  "app", name), encoding="utf-8").read()
          for name in ("main.py", "validate.py", "maintenance.py")}
+# MAINT-21: main.py stands for itself and the files split from it.
+sys.path.insert(0, os.path.join(os.path.dirname(os.path.abspath(__file__)),
+                                "tools"))
+import main_files                            # noqa: E402
+_srcs["main.py"] = main_files.source()
 _literals = {name: re.findall(
     r'"(maintenance_[a-z_]+)"\s*,\s*(-?\d+(?:\.\d+)?)\s*[,)]', src)
     for name, src in _srcs.items()}