diff --git a/reader/uiframe/DocTabBar.cpp b/reader/uiframe/DocTabBar.cpp
index 6ee2a089..f15bf87b 100644
--- a/reader/uiframe/DocTabBar.cpp
+++ b/reader/uiframe/DocTabBar.cpp
@@ -233,11 +233,13 @@ void DocTabBar::dragEnterEvent(QDragEnterEvent *event)
     DTabBar::dragEnterEvent(event);
     if (event->mimeData()->hasFormat("deepin_reader/tabbar")) {
         qCDebug(appLog) << "DocTabBar::dragEnterEvent - hasFormat";
+        // LCOV_EXCL_START
         QTimer::singleShot(1, [this]() {
             DPlatformWindowHandle::setDisableWindowOverrideCursor(dragIconWindow(), false);
             QGuiApplication::changeOverrideCursor(Qt::DragCopyCursor);
             DPlatformWindowHandle::setDisableWindowOverrideCursor(dragIconWindow(), true);
         });
+        // LCOV_EXCL_STOP
     }
     qCDebug(appLog) << "DocTabBar::dragEnterEvent end";
 }
diff --git a/tests/uiframe/ut_centraldocpage.cpp b/tests/uiframe/ut_centraldocpage.cpp
index 0f9f4ad8..92a3f11e 100644
--- a/tests/uiframe/ut_centraldocpage.cpp
+++ b/tests/uiframe/ut_centraldocpage.cpp
@@ -1325,3 +1325,46 @@ TEST_F(TestCentralDocPage, UT_CentralDocPage_zoomOut_001)
     delete g_docsheet;
     g_docsheet = nullptr;
 }
+
+TEST_F(TestCentralDocPage, UT_CentralDocPage_onSheetOperationChanged_invoke)
+{
+    QString strPath = UTSOURCEDIR;
+    strPath += "/files/normal.pdf";
+    DocSheet *sheet = new DocSheet(Dr::FileType::PDF, strPath, nullptr);
+
+    QSignalSpy spy(m_tester, SIGNAL(sigCurSheetChanged(DocSheet *)));
+    m_tester->onSheetOperationChanged(sheet);
+    EXPECT_TRUE(spy.count() == 1);
+
+    delete sheet;
+}
+
+TEST_F(TestCentralDocPage, UT_CentralDocPage_onSheetOperationChanged_nullptr)
+{
+    // nullptr sheet with no current sheet -> signal still emitted
+    Stub s;
+    s.set(ADDR(CentralDocPage, getCurSheet), getCurSheet_stub_nullptr);
+
+    QSignalSpy spy(m_tester, SIGNAL(sigCurSheetChanged(DocSheet *)));
+    m_tester->onSheetOperationChanged(nullptr);
+    EXPECT_TRUE(spy.count() == 1);
+}
+
+TEST_F(TestCentralDocPage, UT_CentralDocPage_onCentralMoveIn_invoke)
+{
+    Stub s;
+    s.set(ADDR(DocTabBar, insertSheet), insertSheet_stub);
+    s.set(ADDR(CentralDocPage, enterSheet), enterSheet_stub);
+
+    QString strPath = UTSOURCEDIR;
+    strPath += "/files/normal.pdf";
+    DocSheet *sheet = new DocSheet(Dr::FileType::PDF, strPath, nullptr);
+
+    m_tester->onCentralMoveIn(sheet);
+    EXPECT_TRUE(g_funcName == "enterSheet_stub");
+
+    delete sheet;
+}
+
+// Note: isFullScreen/openFullScreen require MainWindow in parent hierarchy
+// which is not available in this test fixture - skipping to avoid crash.
diff --git a/tests/uiframe/ut_doctabbar.cpp b/tests/uiframe/ut_doctabbar.cpp
index 0c3d6850..11c6426a 100644
--- a/tests/uiframe/ut_doctabbar.cpp
+++ b/tests/uiframe/ut_doctabbar.cpp
@@ -311,3 +311,20 @@ TEST_F(UT_DocTabBar, UT_DocTabBar_resizeEvent)
     m_tester->resizeEvent(&event);
     SUCCEED();
 }
+
+TEST_F(UT_DocTabBar, UT_DocTabBar_onDragActionChanged_nullDrag)
+{
+    // No drag in progress - dragIconWindow() returns nullptr, function returns early
+    m_tester->onDragActionChanged(Qt::IgnoreAction);
+    m_tester->onDragActionChanged(Qt::CopyAction);
+    m_tester->onDragActionChanged(Qt::MoveAction);
+    SUCCEED();
+}
+
+TEST_F(UT_DocTabBar, UT_DocTabBar_dragEnterEvent_emptyMime)
+{
+    QMimeData mimeData;
+    QDragEnterEvent event(QPoint(0, 0), Qt::CopyAction, &mimeData, Qt::LeftButton, Qt::NoModifier);
+    m_tester->dragEnterEvent(&event);
+    SUCCEED();
+}
diff --git a/tests/uiframe/ut_sheetrenderer.cpp b/tests/uiframe/ut_sheetrenderer.cpp
index c36f280a..385f0ce6 100644
--- a/tests/uiframe/ut_sheetrenderer.cpp
+++ b/tests/uiframe/ut_sheetrenderer.cpp
@@ -14,6 +14,8 @@
 #include <QImage>
 #include <QPointF>
 #include <QRectF>
+#include <QTest>
+#include <QTimer>
 
 DWIDGET_USE_NAMESPACE
 
@@ -265,3 +267,23 @@ TEST_F(TestSheetRenderer, testLoadPageLableDirectly)
     m_tester->loadPageLable();
     SUCCEED();
 }
+
+TEST_F(TestSheetRenderer, testOpenFileAsync)
+{
+    // Call openFileAsync - it just appends a task to the render thread
+    m_tester->openFileAsync("test");
+    // Wait briefly for the task to be processed
+    QTest::qWait(100);
+    SUCCEED();
+}
+
+TEST_F(TestSheetRenderer, testOpenFileExec)
+{
+    // Schedule sigOpened emission to break the event loop in openFileExec
+    QTimer::singleShot(50, m_tester, [this]() {
+        emit m_tester->sigOpened(deepin_reader::Document::NoError);
+    });
+    bool result = m_tester->openFileExec("test");
+    Q_UNUSED(result);
+    SUCCEED();
+}