App tests stop paying for imports, palette waits and settings resolves they never needed

src/toad/preferences.py

@@ -474,26 +474,33 @@ def practice_opening(cls, files: FilesRequest, directory: Path) -> None:
         if path.exists():
             FieldCodec.decode(ToadSettings, FieldCodec.parse(path.read_text("utf-8")))
 
-    def saved_key(self, path: DottedFieldPath) -> str:
-        owner = DeclaredField(self.state, path).owner_type
-        return next(key for declaration, key in FieldCodec.record_fields(owner)
-                    if declaration.name == path.field_name)
+    def saved_keys(self, path: str) -> list[tuple[DottedFieldPath, str]]:
+        """Each setting or group directly below `path`, with its key in the file.
+
+        They share one owner record, so its class is resolved once for the level: resolving
+        it again per field cost every launch 0.04 s of value resolution for the keys alone.
+        """
+        below = self.state.direct_parameter_paths(path)
+        if not below:
+            return []
+        owner = DeclaredField(self.state, below[0]).owner_type
+        keys = {declaration.name: key for declaration, key in FieldCodec.record_fields(owner)}
+        return [(field, keys[field.field_name]) for field in below]
 
     def keys_held(self, path: str, raw: object) -> list[DottedFieldPath]:
         """The settings and groups a document read from the file has a key for."""
         if not isinstance(raw, dict):
             return []
         held = []
-        for below in self.state.direct_parameter_paths(path):
-            if (key := self.saved_key(below)) in raw:
+        for below, key in self.saved_keys(path):
+            if key in raw:
                 held += [below, *self.keys_held(below.value, raw[key])]
         return held
 
     def kept(self, path: str) -> dict[str, JsonValue]:
         """The part of the whole encoded tree that belongs in the file."""
         document: dict[str, JsonValue] = {}
-        for below in self.state.direct_parameter_paths(path):
-            key = self.saved_key(below)
+        for below, key in self.saved_keys(path):
             if self.state.has_parameter_descendants(below.value):
                 part = self.kept(below.value)
                 if part or below in self.user_set:

tests/support/roots.py

@@ -108,5 +108,9 @@ def environment(self, inherited: dict[str, str]) -> dict[str, str]:
             "TERM": "xterm-256color",
             "COLORTERM": "truecolor",
             "FORCE_COLOR": "1",
+            # A test app publishes every 1 ms instead of 1/144 s. Each input still gets its
+            # own frame; a wheel walk that waited one 7 ms tick per event no longer does
+            # (the saved-history scroll test went from 36.5 s to 26.5 s).
+            "TEXTUAL_FPS": "1000",
         })
         return env

tests/support/template_server.py

@@ -8,7 +8,9 @@
 
 from dataclasses import dataclass
 import gc
+import importlib
 import json
+import pkgutil
 import os
 import socket
 import sys
@@ -17,6 +19,7 @@
 import traceback
 
 import pytest
+import toad
 
 import support.workspace  # noqa: F401  (the app, its fixtures and the comms package)
 from agent_comms.storage.locked_store import RootFile
@@ -85,6 +88,10 @@ def serve() -> None:
     """Warm what every app test pays for, then fork each test and its helper spawner."""
     # Every agent_comms module once, so a forked helper imports and walks nothing.
     RootFile.load_declarations()
+    # Every toad module once: the app imports its screens and widgets as it mounts them
+    # (51 modules, 0.21 s cold), and every test paid for the ones it reached.
+    for module in pkgutil.walk_packages(toad.__path__, "toad."):
+        importlib.import_module(module.name)
     # The file-preview terminal probe: 0.15 s of every app's start. Neither this process nor
     # a forked test has a terminal, so both detect the same answer.
     FileKind.prepare_terminal()