Fix height of combo popup when the list view has non-zero spacing.

QListView::spacing() is the space around the item (layout margin),
so the effective spacing is twice as big.
This differs conceptionally from QTableView, which has a spacing of 1
and a line on top/bottom. Split up QComboBoxPrivateContainer::spacing()
into functions return spacing and top/bottom margins to reflect this.

Task-number: QTBUG-37865
Change-Id: I1ff812e7856e00a53f1119ef3304956cbb7cbfca
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@theqtcompany.com>

1 files changed, 20 insertions, 6 deletions

diff --git a/tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp b/tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp
index 54cf1af5d3..f6928f0b35 100644
--- a/tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp
+++ b/tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp
@@ -152,6 +152,7 @@ private slots:
     void resetModel();
     void keyBoardNavigationWithMouse();
     void task_QTBUG_1071_changingFocusEmitsActivated();
+    void maxVisibleItems_data();
     void maxVisibleItems();
     void task_QTBUG_10491_currentIndexAndModelColumn();
     void highlightedSignal();
@@ -2749,8 +2750,18 @@ void tst_QComboBox::task_QTBUG_1071_changingFocusEmitsActivated()
     QTRY_COMPARE(spy.count(), 1);
 }
 
+void tst_QComboBox::maxVisibleItems_data()
+{
+    QTest::addColumn<int>("spacing");
+    QTest::newRow("Default")  << -1;
+    QTest::newRow("No spacing") << 0;
+    QTest::newRow("20")  << -1;
+}
+
 void tst_QComboBox::maxVisibleItems()
 {
+    QFETCH(int, spacing);
+
     QComboBox comboBox;
     QCOMPARE(comboBox.maxVisibleItems(), 10); //default value.
 
@@ -2771,15 +2782,18 @@ void tst_QComboBox::maxVisibleItems()
     QTRY_VERIFY(comboBox.view());
     QTRY_VERIFY(comboBox.view()->isVisible());
 
-    QAbstractItemView *v = comboBox.view();
-    int itemHeight = v->visualRect(v->model()->index(0,0)).height();
-    QListView *lv = qobject_cast<QListView*>(v);
-    if (lv)
-        itemHeight += lv->spacing();
+    QListView *listView = qobject_cast<QListView*>(comboBox.view());
+    QVERIFY(listView);
+    if (spacing >= 0)
+        listView->setSpacing(spacing);
+
+    const int itemHeight = listView->visualRect(listView->model()->index(0,0)).height()
+        + 2 * listView->spacing();
+
     QStyleOptionComboBox opt;
     opt.initFrom(&comboBox);
     if (!comboBox.style()->styleHint(QStyle::SH_ComboBox_Popup, &opt))
-        QCOMPARE(v->viewport()->height(), itemHeight * comboBox.maxVisibleItems());
+        QCOMPARE(listView->viewport()->height(), itemHeight * comboBox.maxVisibleItems());
 }
 
 void tst_QComboBox::task_QTBUG_10491_currentIndexAndModelColumn()