Add test for LtsTimelineClassic TimelineHeaderView.cpp

- Added test_timelineheaderview.cpp with 3 tests
- Tests cover constructor, setPosMarkTime, and setLiveTime

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

qt6-after/qt6-migrated-benchmark/tests/test_timelineheaderview.cpp

@@ -0,0 +1,52 @@
+#include "Lts/Common/LtsTimelineClassic/TimelineHeaderView.h"
+
+#include <QApplication>
+#include <gtest/gtest.h>
+
+namespace LtsTimelineClassic
+{
+
+class TimelineHeaderViewTest : public ::testing::Test
+{
+  protected:
+    void SetUp() override
+    {
+        int argc = 1;
+        char* argv[] = {const_cast<char*>("test")};
+        qApp = new QApplication(argc, argv);
+    }
+
+    void TearDown() override
+    {
+        delete qApp;
+        qApp = nullptr;
+    }
+};
+
+TEST(TimelineHeaderViewTest, ConstructorCreatesValidHeader)
+{
+    QWidget parent;
+    TimelineHeaderView header(&parent);
+    EXPECT_NE(header.count(), -1);
+    EXPECT_TRUE(header.stretchLastSection());
+}
+
+TEST(TimelineHeaderViewTest, SetPosMarkTimeUpdatesValue)
+{
+    QWidget parent;
+    TimelineHeaderView header(&parent);
+
+    EXPECT_NO_THROW(header.setPosMarkTime(1000));
+    EXPECT_NO_THROW(header.setPosMarkTime(5000));
+}
+
+TEST(TimelineHeaderViewTest, SetLiveTimeUpdatesValue)
+{
+    QWidget parent;
+    TimelineHeaderView header(&parent);
+
+    EXPECT_NO_THROW(header.setLiveTime(1000));
+    EXPECT_NO_THROW(header.setLiveTime(5000));
+}
+
+} // namespace LtsTimelineClassic