Add baseline test that allows comparing the rendering of widgets

Provide basic boiler plate that sets up the baseline (aka lancelot)
framework specifically for comparing the appearance of widgets, and
implement test functions for QSlider and QPushButton.

Widgets should always look the same if the QPA platform, the OS
version, and certain UI-impacting attributes are identical. Ie.
on any macOS 10.15 machine that runs in "Light" mode, widgets
look the same. On a macOS 11 machine, they might look different.
On an OpenSUSE machine using the fusion style things might look
different from a Ubuntu machine.

The helper function removes DPR differences - images are always
scaled to a DPR of 1.0, which allows us to compare the image\
content and not get distracted by them having different dimensions
(and the fuzzy comparison of images might make the system tolerate
scaling artefacts).

Note: For now, this test is meant to be run locally, either when
testing changes to style code, or when checking how QWidget based
UIs would look on newer version of an operating system. In CI the
test is run, but then skipped in CI as the baseline server is
not configured.

Change-Id: Ie33a9d979d934f0df6883757333ce2c5e2f7ef84
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

1 files changed, 12 insertions, 0 deletions

diff --git a/tests/baseline/widgets/CMakeLists.txt b/tests/baseline/widgets/CMakeLists.txt
new file mode 100644
index 0000000000..eac3ca6753
--- /dev/null
+++ b/tests/baseline/widgets/CMakeLists.txt
@@ -0,0 +1,12 @@
+qt_internal_add_test(tst_baseline_widgets
+    SOURCES
+        ../shared/baselineprotocol.cpp ../shared/baselineprotocol.h ../shared/lookup3.cpp
+        ../shared/qbaselinetest.cpp ../shared/qbaselinetest.h
+        tst_baseline_widgets.cpp
+    INCLUDE_DIRECTORIES
+        ../shared
+    PUBLIC_LIBRARIES
+        Qt::Gui
+        Qt::Widgets
+        Qt::Network
+)