Add test for LtsTimelineClassic TestTimelineModel.cpp

- Added test_testtimelinemodel.cpp with 3 tests
- Tests cover constructor, addTestEvent, and multiple event addition

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

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

@@ -0,0 +1,51 @@
+#include "Lts/Common/LtsTimelineClassic/Event.h"
+#include "Lts/Common/LtsTimelineClassic/TestTimelineModel.h"
+
+#include <gtest/gtest.h>
+
+namespace LtsTimelineClassic
+{
+
+class TestTimelineModelTest : public ::testing::Test
+{
+  protected:
+    void SetUp() override {}
+
+    void TearDown() override {}
+};
+
+TEST(TestTimelineModelTest, ConstructorCreatesValidModel)
+{
+    TestTimelineModel model;
+    EXPECT_NO_THROW(model.rowCount());
+    EXPECT_NO_THROW(model.columnCount());
+}
+
+TEST(TestTimelineModelTest, AddTestEventIncreasesRowCount)
+{
+    TestTimelineModel model;
+    int initialCount = model.rowCount();
+
+    Event* event = new Event();
+    model.addTestEvent(event);
+
+    EXPECT_EQ(model.rowCount(), initialCount + 1);
+}
+
+TEST(TestTimelineModelTest, MultipleEventsCanBeAdded)
+{
+    TestTimelineModel model;
+    int initialCount = model.rowCount();
+
+    Event* event1 = new Event();
+    Event* event2 = new Event();
+    Event* event3 = new Event();
+
+    model.addTestEvent(event1);
+    model.addTestEvent(event2);
+    model.addTestEvent(event3);
+
+    EXPECT_EQ(model.rowCount(), initialCount + 3);
+}
+
+} // namespace LtsTimelineClassic