Reworked and cleaned up client-side TabSheet and Accordion. (#12357)

- Added and corrected JavaDocs.
- Deprecated unused public methods.
- Fixed first tab style logic in TabSheet.
- Fixed navigation focus logic in TabSheet.
- Fixed tab width bookkeeping for scrolling TabSheet tabs.
- Renamed private methods and variables for clarity.
- Removed unnecessary or duplicated private methods.
- Reworked some logic to clarify it and to better match my understanding
of what's supposed to happen within those methods.
- Updated some deprecated method calls to use currently recommended
solutions.
- Added and updated regression tests.

2 files changed, 29 insertions, 5 deletions

diff --git a/uitest/src/main/java/com/vaadin/tests/components/tabsheet/ScrolledTabSheetHiddenTabsResize.java b/uitest/src/main/java/com/vaadin/tests/components/tabsheet/ScrolledTabSheetHiddenTabsResize.java
new file mode 100644
index 0000000000..6584cd69a5
--- /dev/null
+++ b/uitest/src/main/java/com/vaadin/tests/components/tabsheet/ScrolledTabSheetHiddenTabsResize.java
@@ -0,0 +1,20 @@
+package com.vaadin.tests.components.tabsheet;
+
+import com.vaadin.ui.Label;
+import com.vaadin.ui.TabSheet;
+import com.vaadin.ui.TabSheet.Tab;
+
+public class ScrolledTabSheetHiddenTabsResize extends ScrolledTabSheetResize {
+
+    @Override
+    protected void populate(TabSheet tabSheet) {
+        for (int i = 0; i < 40; i++) {
+            String caption = "Tab " + i;
+            Label label = new Label(caption);
+
+            Tab tab = tabSheet.addTab(label, caption);
+            tab.setClosable(true);
+            tab.setVisible(i % 2 != 0);
+        }
+    }
+}
diff --git a/uitest/src/main/java/com/vaadin/tests/components/tabsheet/ScrolledTabSheetResize.java b/uitest/src/main/java/com/vaadin/tests/components/tabsheet/ScrolledTabSheetResize.java
index c84ba5e3ef..28b37ec4e4 100644
--- a/uitest/src/main/java/com/vaadin/tests/components/tabsheet/ScrolledTabSheetResize.java
+++ b/uitest/src/main/java/com/vaadin/tests/components/tabsheet/ScrolledTabSheetResize.java
@@ -21,6 +21,15 @@ public class ScrolledTabSheetResize extends AbstractTestUI {
         TabSheet tabSheet = new TabSheet();
         tabSheet.setSizeFull();
 
+        populate(tabSheet);
+
+        addComponent(tabSheet);
+        addComponent(new Button("use reindeer", e -> {
+            setTheme("reindeer");
+        }));
+    }
+
+    protected void populate(TabSheet tabSheet) {
         for (int i = 0; i < 20; i++) {
             String caption = "Tab " + i;
             Label label = new Label(caption);
@@ -28,11 +37,6 @@ public class ScrolledTabSheetResize extends AbstractTestUI {
             Tab tab = tabSheet.addTab(label, caption);
             tab.setClosable(true);
         }
-
-        addComponent(tabSheet);
-        addComponent(new Button("use reindeer", e -> {
-            setTheme("reindeer");
-        }));
     }
 
     @Override