From dea2d70855ad21c591d360f859c46bf826edde51 Mon Sep 17 00:00:00 2001
From: Glen Beane <356266+gbeane@users.noreply.github.com>
Date: Thu, 5 Nov 2026 14:11:39 -0500
Subject: [PATCH] Run Qt tests offscreen so they don't open windows

---
 tests/conftest.py                     | 8 ++++++++
 tests/ui/test_postprocessing_group.py | 4 +++-
 2 files changed, 11 insertions(+), 1 deletion(-)
 create mode 100644 tests/conftest.py

diff --git a/tests/conftest.py b/tests/conftest.py
new file mode 100644
index 00000000..cb09c760
--- /dev/null
+++ b/tests/conftest.py
@@ -0,0 +1,8 @@
+"""Shared test configuration for the application test suite."""
+
+import os
+
+# Render Qt widgets offscreen so UI tests don't open windows and steal focus. Set before
+# any test module creates a QApplication; override with e.g. QT_QPA_PLATFORM=cocoa to
+# watch the widgets.
+os.environ.setdefault("QT_QPA_PLATFORM", "offscreen")
diff --git a/tests/ui/test_postprocessing_group.py b/tests/ui/test_postprocessing_group.py
index 4c3a05ef..b3e81bc3 100644
--- a/tests/ui/test_postprocessing_group.py
+++ b/tests/ui/test_postprocessing_group.py
@@ -218,7 +218,9 @@ def test_parameter_spinbox_is_sized_for_display_maximum() -> None:
     full_range_reference.setRange(1, _INT_MAX)
 
     width = spinbox.sizeHint().width()
-    assert width == display_reference.sizeHint().width()
+    # the hint subtracts two text widths that Qt rounds to whole pixels, so it can land
+    # one pixel off the reference
+    assert abs(width - display_reference.sizeHint().width()) <= 1
     assert width < full_range_reference.sizeHint().width()