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## This file is part of the test suite of PySide2.
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import unittest

from PySide2.QtGui import QStandardItemModel
from PySide2.QtWidgets import QWidget, QTreeView, QVBoxLayout, QStyledItemDelegate
from helper import UsesQApplication

class Widget(QWidget):
    def __init__(self, parent=None):
        QWidget.__init__(self, parent)
        self.treeView = QTreeView(self)
        layout = QVBoxLayout()
        layout.addWidget(self.treeView)
        self.setLayout(layout)
        self.treeView.setModel(QStandardItemModel())

        self.treeView.model().setHorizontalHeaderLabels(('3', '1', '5'))

class QWidgetTest(UsesQApplication):

    def testDelegates(self):
        widget = Widget()
        t = widget.treeView

        # When calling setItemDelegateForColumn using a separate variable
        # for the second argument (QAbstractItemDelegate), there was no problem
        # on keeping the reference to this object, since the variable was kept
        # alive (case A)
        # Contrary, when instantiating this argument on the function call
        # Using QStyledItemDelegate inside the call the reference of the
        # object was lost, causing a segfault. (case B)

        # Case A
        d = QStyledItemDelegate()
        # Using QStyledItemDelegate from a variable so we keep the reference alive
        # and we encounter no segfault.
        t.setItemDelegateForColumn(0, d)
        # This raised the Segmentation Fault too, because manually destroying
        # the object caused a missing refrence.
        del d

        # Getting the delegates
        a = t.itemDelegateForColumn(0)
        self.assertIsInstance(a, QStyledItemDelegate)

        # Case B
        t.setItemDelegateForColumn(1, QStyledItemDelegate())

        # Getting the delegates
        b = t.itemDelegateForColumn(1)
        self.assertIsInstance(b, QStyledItemDelegate)

        # Test for Rows
        t.setItemDelegateForRow(0, QStyledItemDelegate())
        self.assertIsInstance(t.itemDelegateForRow(0), QStyledItemDelegate)

        # Test for general delegate
        t.setItemDelegate(QStyledItemDelegate())
        self.assertIsInstance(t.itemDelegate(), QStyledItemDelegate)

if __name__ == '__main__':
    unittest.main()