TestAssemblySetup set the unhandled-exception mode and a ThreadException
handler from a module initializer. WinForms stores both per thread
(ThreadContext/NativeWindow thread statics), so they applied only to the
runner thread that loaded the assembly, never to the STA threads the
tests run on. There, an exception escaping a window message or a
BeginInvoke/SynchronizationContext callback still opened a modal
ThreadExceptionDialog in an interactive session, or was silently ignored
otherwise; the handler would also have logged and swallowed it.
Replace the fifteen copied RunSta helpers with StaTestThread.Run, which
selects UnhandledExceptionMode.ThrowException on each STA thread before
it creates a window, so the exception propagates to the test body and
fails the test. Each class keeps its own timeout and message; all
threads are now background threads. Remove TestAssemblySetup.
StaTestThreadTests covers a throwing BeginInvoke callback through
StaTestThread (fails with the original exception) and, as a control,
the default mode on a plain STA thread (the exception goes to the
thread's handler and never reaches the test body). Cross-compiled on
Linux; Windows execution is the windows-desktop CI job.
The new windows-desktop CI job surfaced several tests that had never
actually run on Windows:
- SeparatorPenLifetimeTests expected Control.Disposed to fire only
once; current WinForms re-fires it on every Dispose() call.
- EditNestFocusTraversalTests assumed the Plates tab was selected by
default, which stopped being true once Drawings became the landing
tab; select it explicitly before asserting focus.
- NestReportExportTests asserted an exact plate count that ignored
PlateManager's trailing sentinel plate, and didn't expect the nest
name in the busy-export message.
- AtomicReportFileTests only expected IOException when replacing a
directory target; Windows raises UnauthorizedAccessException instead,
which callers already treat the same way.
Also register a ThreadException handler so an exception inside a
WndProc callback fails the test normally instead of popping a modal
dialog that blocks the desktop.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
The reorder event snapshot could previously show the reverse pass's
stale timeout label. Set a sentinel before each click so the
ProgramChanged handler can only observe the label applied by the
current operation's highlighting pass.
Quality review of 50884da found the unshown RichTextBox oracle compared
cached CRLF text against the highlighted editor's native LF-normalized
text, which would fail on first Windows execution. Compare generated
text with normalized line endings on both sides instead, capture the
status label and preview state inside the ProgramChanged handler to
prove fallback-before-notify ordering, document the HighlightSpan
UTF-16 and rule-index contract, and pin the null-text argument check.
aj
