Verifying LiveMarkDownEditor

WPF app, net10.0-windows. Tests are headless STA (StaThread.Run) and cannot observe layout, focus, undo, or command availability — drive the real app for anything in that list.

Build and launch

A running UI.exe locks bin/, so always build to a scratch output:

dotnet build src/UI/UI.csproj -c Debug -o "<scratch>/app" --nologo -v q

Launch with an optional Startup Document (the app takes a .md path as argv[1] — the quickest way to get a document with headings/tables in front of you without driving the Open dialog):

$proc = Start-Process "<scratch>/app/UI.exe" -ArgumentList "<scratch>/test.md" -PassThru

Poll for the window — MainWindowHandle is 0 for a second or two after Start-Process, and reading it too early yields an empty handle:

for ($i = 0; $i -lt 40; $i++) {
    Start-Sleep -Milliseconds 500
    $l = Get-Process -Id $proc.Id -ErrorAction SilentlyContinue
    $l.Refresh()
    if ($l.MainWindowHandle -ne 0) { $h = $l.MainWindowHandle; break }
}

Screenshot

PrintWindow with flag 2 (PW_RENDERFULLCONTENT) — flag 0 renders WPF content blank. Capture the window even when it is not foreground.

Drive it

• Click into the editing area first (SetCursorPos + mouse_event, ~(400, 300) window-relative). The RichTextBox does not have focus at startup, so SendKeys goes nowhere and you get a confusingly empty document.
• Then SetForegroundWindow + [System.Windows.Forms.SendKeys]::SendWait(...), ~600ms between steps.
• Command bar hit points (maximized, 1936px wide): Source panel toggle ~(681, 55), Collapse all ~(435, 55), Expand all ~(523, 55). Turn the Source panel on to watch Capture happen live — it is the clearest proof an edit reached the Markdown Document.

Gotchas

• The Find Bar floats over the top-right, which is exactly where the Source Panel is. Its first couple of source lines sit behind the bar — close the Find Bar (its ✕, ~(1875, 162)) before concluding the Source Panel is empty.
• Escape only closes the Find Bar while focus is in the query/replacement box — it is bound on those TextBox.InputBindings, not globally. From the editor, click the ✕ instead.
• RoutedUICommand.Execute() bypasses CanExecute. A command can be dead in the UI (greyed out) while its unit test passes happily. If a change adds or alters a command, assert CanExecute in the test and look at the button in a screenshot.