class TestButton(QtGui.QPushButton):
    def __init__(self, contents, parent=None):
        super(TestButton, self).__init__(contents, parent)
        layout = QtGui.QStackedLayout()
        self.isTextVisible = False
        self.textEdit = QtGui.QLineEdit("Testing", self)
        layout.addWidget(self.textEdit)
        self.setLayout(layout)
        self.__setupTextEdit()

    def __setupTextEdit(self):
        self.textEdit.setVisible(self.isTextVisible)

    def showTextEdit(self):
        self.isTextVisible = not self.isTextVisible
        self.textEdit.setVisible(self.isTextVisible)

class Example(QtGui.QWidget):
    def __init__(self, parent=None):
        QtGui.QWidget.__init__(self, parent=parent)
        self.masterLayout = QtGui.QVBoxLayout()
        self.btn = TestButton("Test Me")
        self.btn.clicked.connect(self.openText)
        self.masterLayout.addWidget(self.breakUndoButton)
        self.setLayout(self.masterLayout)

    def openText(self):
        self.btn.showTextEdit()