from PyQt5.QtWidgets import *
import sys


class MyWindow(QWidget):
    def __init__(self):
        super(MyWindow, self).__init__()
        self.resize(300, 250)
        vb = QVBoxLayout()
        self.setLayout(vb)
        self.but1 = QPushButton('Save')
        self.text1 = QTextEdit()
        self.le1 = QLineEdit()
        self.le2 = QLineEdit()
        self.but2 = QPushButton('Open')
        self.text2 = QTextEdit()
        self.le3 = QLineEdit()
        self.le4 = QLineEdit()
        vb.addWidget(self.but1)
        vb.addWidget(self.text1)
        vb.addWidget(self.le1)
        vb.addWidget(self.le2)
        vb.addWidget(self.but2)
        vb.addWidget(self.text2)
        vb.addWidget(self.le3)
        vb.addWidget(self.le4)
        self.but1.clicked.connect(self.save_file)
        self.but2.clicked.connect(self.open_file)
        self.show()

    def save_file(self):
        f = open( "test.txt" ,'w' )
        for item in self.text1.toPlainText():
            f.write(item)
        f.write('\n')
        f.write("---")
        f.write('\n')
        f.write(self.le1.text())
        f.write('\n')
        f.write(self.le2.text())
        f.write('\n')

        f.close()

    def open_file(self):
        f = open('test.txt')
        for line in f.readlines():
            self.text2.setText(line)
        f.close()
      

if __name__ == '__main__':
    app = QApplication(sys.argv)
    window = MyWindow()
    sys.exit(app.exec_())

  def open_file(self):
        f = open('test.txt')
        for line in f.readlines():
            self.text2.append(line)
        f.close()

             self.text2.append(line.rstrip())