Add some tests for NotebookTab (#5070)

* EmptyApplication: Add asserts to rest of getters (except for getSeventvAPI)

* Theme: make getTheme call getIApp()->getThemes() instead

this allows it to be used in tests
realistically this should be deprecated & users of it should just call
getIApp()->getThemes() directly

* Use getIApp() instead of getApp() in a few places

src/widgets/helper/NotebookTab.cpp

@@ -93,8 +93,8 @@ NotebookTab::NotebookTab(Notebook *notebook)
         [this]() {
             this->notebook_->removePage(this->page);
         },
-        getApp()->hotkeys->getDisplaySequence(HotkeyCategory::Window,
-                                              "removeTab"));
+        getIApp()->getHotkeys()->getDisplaySequence(HotkeyCategory::Window,
+                                                    "removeTab"));
 
     this->menu_.addAction(
         "Popup Tab",
@@ -104,8 +104,8 @@ NotebookTab::NotebookTab(Notebook *notebook)
                 container->popup();
             }
         },
-        getApp()->hotkeys->getDisplaySequence(HotkeyCategory::Window, "popup",
-                                              {{"window"}}));
+        getIApp()->getHotkeys()->getDisplaySequence(HotkeyCategory::Window,
+                                                    "popup", {{"window"}}));
 
     highlightNewMessagesAction_ =
         new QAction("Mark Tab as Unread on New Messages", &this->menu_);
@@ -196,7 +196,7 @@ int NotebookTab::normalTabWidth()
     float scale = this->scale();
     int width;
 
-    QFontMetrics metrics = getApp()->fonts->getFontMetrics(
+    auto metrics = getIApp()->getFonts()->getFontMetrics(
         FontStyle::UiTabs, float(qreal(this->scale()) * deviceDpi(this)));
 
     if (this->hasXButton())
@@ -359,6 +359,11 @@ void NotebookTab::setHighlightState(HighlightState newHighlightStyle)
     }
 }
 
+HighlightState NotebookTab::highlightState() const
+{
+    return this->highlightState_;
+}
+
 void NotebookTab::setHighlightsEnabled(const bool &newVal)
 {
     this->highlightNewMessagesAction_->setChecked(newVal);
@@ -783,6 +788,11 @@ void NotebookTab::wheelEvent(QWheelEvent *event)
     }
 }
 
+void NotebookTab::update()
+{
+    Button::update();
+}
+
 QRect NotebookTab::getXRect()
 {
     QRect rect = this->rect();