Improve verifyEmptyTabTray Ui test coverage

app/src/androidTest/java/org/mozilla/fenix/ui/TabbedBrowsingTest.kt

@@ -298,10 +298,16 @@ class TabbedBrowsingTest {
     fun verifyEmptyTabTray() {
         navigationToolbar {
         }.openTabTray {
+            verifyNormalBrowsingButtonIsSelected(true)
+            verifyPrivateBrowsingButtonIsSelected(false)
+            verifySyncedTabsButtonIsSelected(false)
             verifyNoTabsOpened()
             verifyNewTabButton()
             verifyTabTrayOverflowMenu(true)
         }.toggleToPrivateTabs {
+            verifyNormalBrowsingButtonIsSelected(false)
+            verifyPrivateBrowsingButtonIsSelected(true)
+            verifySyncedTabsButtonIsSelected(false)
             verifyNoTabsOpened()
             verifyNewTabButton()
             verifyTabTrayOverflowMenu(true)

app/src/androidTest/java/org/mozilla/fenix/ui/robots/TabDrawerRobot.kt

@@ -46,6 +46,7 @@ import org.mozilla.fenix.helpers.click
 import org.mozilla.fenix.helpers.clickAtLocationInView
 import org.mozilla.fenix.helpers.ext.waitNotNull
 import org.mozilla.fenix.helpers.idlingresource.BottomSheetBehaviorStateIdlingResource
+import org.mozilla.fenix.helpers.isSelected
 import org.mozilla.fenix.helpers.matchers.BottomSheetBehaviorHalfExpandedMaxRatioMatcher
 import org.mozilla.fenix.helpers.matchers.BottomSheetBehaviorStateMatcher
 
@@ -66,6 +67,12 @@ class TabDrawerRobot {
     }
 
     fun verifyNormalBrowsingButtonIsDisplayed() = assertNormalBrowsingButton()
+    fun verifyNormalBrowsingButtonIsSelected(isSelected: Boolean) =
+        assertNormalBrowsingButtonIsSelected(isSelected)
+    fun verifyPrivateBrowsingButtonIsSelected(isSelected: Boolean) =
+        assertPrivateBrowsingButtonIsSelected(isSelected)
+    fun verifySyncedTabsButtonIsSelected(isSelected: Boolean) =
+        assertSyncedTabsButtonIsSelected(isSelected)
     fun verifyExistingOpenTabs(title: String) = assertExistingOpenTabs(title)
     fun verifyCloseTabsButton(title: String) = assertCloseTabsButton(title)
 
@@ -450,6 +457,7 @@ private fun normalBrowsingButton() = onView(
 )
 
 private fun privateBrowsingButton() = onView(withContentDescription("Private tabs"))
+private fun syncedTabsButton() = onView(withContentDescription("Synced tabs"))
 private fun newTabButton() = mDevice.findObject(UiSelector().resourceId("$packageName:id/new_tab_button"))
 private fun threeDotMenu() = onView(withId(R.id.tab_tray_overflow))
 
@@ -542,6 +550,18 @@ private fun assertNormalBrowsingButton() {
     normalBrowsingButton().check(matches(withEffectiveVisibility(ViewMatchers.Visibility.VISIBLE)))
 }
 
+private fun assertNormalBrowsingButtonIsSelected(isSelected: Boolean) {
+    normalBrowsingButton().check(matches(isSelected(isSelected)))
+}
+
+private fun assertPrivateBrowsingButtonIsSelected(isSelected: Boolean) {
+    privateBrowsingButton().check(matches(isSelected(isSelected)))
+}
+
+private fun assertSyncedTabsButtonIsSelected(isSelected: Boolean) {
+    syncedTabsButton().check(matches(isSelected(isSelected)))
+}
+
 private fun assertTabThumbnail() {
     assertTrue(
         mDevice.findObject(