ThemeManager grows a test seam — its singleton ctor now delegates to
three internal seams (isSystemDark / loadPreference / savePreference)
that the production singleton fills with the real registry +
UIPreferences calls. Tests construct via the internal ctor with
stubs so they never touch HKCU or %LOCALAPPDATA% (which would
otherwise flake on CI or pollute the dev's UI state). Apply() and
the SystemEvents subscription are intentionally NOT exercised
here — both require Application.Current and a real dispatcher.
CommandPaletteViewModel.Matches changes from `private static` to
`internal static` — the predicate is the unit worth pinning, and
building a full CommandPaletteViewModel would require a fake
IIsoController + Dispatcher for one test.
New tests:
* src/tests/TeamsISO.App.Tests/Services/ThemeManagerTests.cs (11 cases):
- Set Dark → Light round-trips Preference + ResolveTheme and
persists via the savePreference seam.
- ResolveTheme follows the system probe when Preference is
System (true → Dark, false → Light).
- Toggle from System pins to the opposite of the currently-
resolved theme (not back to System) — explicit click should
have visible effect.
- Toggle from Dark flips Light; Toggle from Light flips Dark.
- Set rejects invalid preferences (case-sensitive: lowercase
"dark", "LIGHT", "", "invalid" all throw ArgumentException
with ParamName=preference).
- Constructor defaults to System when loadPreference returns
null (fresh install / missing prefs file) or an invalid value
(future schema collision).
- Constructor swallows a load exception so the app doesn't lose
theming when ui-prefs.json faults on read.
* src/tests/TeamsISO.App.Tests/ViewModels/CommandPaletteMatchesTests.cs
(16 cases): Theory pinning case-insensitive label / category /
keyword Contains, plus a full-vocabulary spread test counting
hits for "theme" (3), "stop" (1), "ndi" (2), "App" (5 — four
App-category cmds + the Apply transcoder topology substring
match, called out in the assertion because a future move to a
stricter algo has to re-decide that affordance deliberately),
and "xyzzy" (0).
Tests: 56 → 83 in App.Tests; Engine.Tests unchanged at 103.
Total green: 186. Build clean.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
