使用 Pytest 测试 class 方法

Question

我现在正在上一门编程课程，CSE 111 programming with functions，我的最后一个任务是找到一个有趣的代码并编写一些测试函数，以测试代码是否正确工作。 这是代码：

#Imported modules
import sys
import wave, contextlib, math, time
import speech_recognition as sr
from moviepy.editor import AudioFileClip
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtWidgets import QFileDialog, QMessageBox
from PyQt5.QtCore import QThread, pyqtSignal

class Ui_MainWindow(object):
    """Main window GUI."""
    def __init__(self):
        """Initialisation function."""
        self.mp4_file_name = ""
        self.output_file = ""
        self.audio_file = "speech.wav"
    def setupUi(self, MainWindow):
        """Define visual components and positions."""
        # Main window
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(653, 836)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.label = QtWidgets.QLabel(self.centralwidget)
        self.label.setGeometry(QtCore.QRect(50, 20, 161, 41))
        # Selected video file label
        font = QtGui.QFont()
        font.setPointSize(14)
        self.label.setFont(font)
        self.label.setObjectName("label")
        self.selected_video_label = QtWidgets.QLabel(self.centralwidget)
        self.selected_video_label.setGeometry(QtCore.QRect(230, 20, 371, 41))
        font = QtGui.QFont()
        font.setPointSize(8)
        self.selected_video_label.setFont(font)
        self.selected_video_label.setFrameShape(QtWidgets.QFrame.Box)
        self.selected_video_label.setText("")
        self.selected_video_label.setObjectName("selected_video_label")
        self.label_3 = QtWidgets.QLabel(self.centralwidget)
        self.label_3.setGeometry(QtCore.QRect(50, 90, 161, 41))
        # Transcribed text box
        font = QtGui.QFont()
        font.setPointSize(14)
        self.label_3.setFont(font)
        self.label_3.setObjectName("label_3")
        self.transcribed_text = QtWidgets.QTextBrowser(self.centralwidget)
        self.transcribed_text.setGeometry(QtCore.QRect(230, 320, 381, 431))
        self.transcribed_text.setObjectName("transcribed_text")
        self.label_5 = QtWidgets.QLabel(self.centralwidget)
        self.label_5.setGeometry(QtCore.QRect(230, 280, 161, 41))
        font = QtGui.QFont()
        font.setPointSize(14)
        self.label_5.setFont(font)
        self.label_5.setObjectName("label_5")
        self.transcribe_button = QtWidgets.QPushButton(self.centralwidget)
        self.transcribe_button.setEnabled(False)
        self.transcribe_button.setGeometry(QtCore.QRect(230, 150, 221, 81))
        # Transcribe button
        font = QtGui.QFont()
        font.setPointSize(14)
        self.transcribe_button.setFont(font)
        self.transcribe_button.setObjectName("transcribe_button")
        self.transcribe_button.clicked.connect(self.process_and_transcribe_audio)
        # progeress bar
        self.progress_bar = QtWidgets.QProgressBar(self.centralwidget)
        self.progress_bar.setGeometry(QtCore.QRect(230, 250, 381, 23))
        self.progress_bar.setProperty("value", 0)
        self.progress_bar.setObjectName("progress_bar")
        self.message_label = QtWidgets.QLabel(self.centralwidget)
        self.message_label.setGeometry(QtCore.QRect(0, 760, 651, 21))
        # Message label (for errors and warnings)
        font = QtGui.QFont()
        font.setPointSize(8)
        self.message_label.setFont(font)
        self.message_label.setFrameShape(QtWidgets.QFrame.Box)
        self.message_label.setText("")
        self.message_label.setObjectName("message_label")
        self.output_file_name = QtWidgets.QPlainTextEdit(self.centralwidget)
        self.output_file_name.setGeometry(QtCore.QRect(230, 90, 371, 41))
        # Output file name
        font = QtGui.QFont()
        font.setPointSize(14)
        self.output_file_name.setFont(font)
        self.output_file_name.setObjectName("output_file_name")
        # Menubar options
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 653, 21))
        self.menubar.setObjectName("menubar")
        self.menuFile = QtWidgets.QMenu(self.menubar)
        self.menuFile.setObjectName("menuFile")
        self.menuAbout = QtWidgets.QMenu(self.menubar)
        self.menuAbout.setObjectName("menuAbout")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)
        self.actionOpen_mp4_video_recording = QtWidgets.QAction(MainWindow)
        self.actionOpen_mp4_video_recording.setObjectName("actionOpen_mp4_video_recording")
        self.actionOpen_mp4_video_recording.triggered.connect(self.open_audio_file)
        self.actionAbout_vid2text = QtWidgets.QAction(MainWindow)
        self.actionAbout_vid2text.setObjectName("actionAbout_vid2text")
        self.actionAbout_vid2text.triggered.connect(self.show_about)
        self.actionNew = QtWidgets.QAction(MainWindow)
        self.actionNew.setObjectName("actionNew")
        self.actionNew.triggered.connect(self.new_project)
        self.menuFile.addAction(self.actionOpen_mp4_video_recording)
        self.menuFile.addAction(self.actionNew)
        self.menuAbout.addAction(self.actionAbout_vid2text)
        self.menubar.addAction(self.menuFile.menuAction())
        self.menubar.addAction(self.menuAbout.menuAction())
        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)
    def retranslateUi(self, MainWindow):
        """Translate UI method."""
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
        self.label.setText(_translate("MainWindow", "Selected video file:"))
        self.label_3.setText(_translate("MainWindow", "Output file name:"))
        self.label_5.setText(_translate("MainWindow", "Transcribed text:"))
        self.transcribe_button.setText(_translate("MainWindow", "Transcribe"))
        self.output_file_name.setPlaceholderText(_translate("MainWindow", "interview1.txt"))
        self.menuFile.setTitle(_translate("MainWindow", "File"))
        self.menuAbout.setTitle(_translate("MainWindow", "About"))
        self.actionOpen_mp4_video_recording.setText(_translate("MainWindow", "Open mp4 video recording"))
        self.actionAbout_vid2text.setText(_translate("MainWindow", "About video to speech"))
        self.actionNew.setText(_translate("MainWindow", "New"))
    def open_audio_file(self):
        """Open the audio (*.mp4) file."""
        file_name = QFileDialog.getOpenFileName()
        if file_name[0][-3:] == "mp4":
            self.transcribe_button.setEnabled(True)
            self.mp4_file_name = file_name[0]
            self.selected_video_label.setText(file_name[0])
        else:
            self.message_label.setText("Please select an *.mp4 file")
    def convert_mp4_to_wav(self):
        """Convert the mp4 video file into an audio file."""
        self.message_label.setText("Converting mp4 to audio (*.wav)...")
        self.convert_thread = convertVideoToAudioThread(self.mp4_file_name, self.audio_file)
        self.convert_thread.finished.connect(self.finished_converting)
        self.convert_thread.start()
    def get_audio_duration(self, audio_file):
        """Determine the length of the audio file."""
        with contextlib.closing(wave.open(audio_file,'r')) as f:
            frames = f.getnframes()
            rate = f.getframerate()
            duration = frames / float(rate)
            return duration
    def transcribe_audio(self, audio_file):
        """Transcribe the audio file."""
        total_duration = self.get_audio_duration(audio_file) / 10
        total_duration = math.ceil(total_duration)
        self.td = total_duration
        if len(self.output_file_name.toPlainText()) > 0:
            self.output_file = self.output_file_name.toPlainText()
        else:
            self.output_file = "my_speech_file.txt"
        # Use thread to process in the background and avoid freezing the GUI
        self.thread = transcriptionThread(total_duration, audio_file, self.output_file)
        self.thread.finished.connect(self.finished_transcribing)
        self.thread.change_value.connect(self.set_progress_value)
        self.thread.start()
    def finished_converting(self):
        """Reset message text when conversion is finished."""
        self.message_label.setText("Transcribing file...")
        self.transcribe_audio(self.audio_file)
    def finished_transcribing(self):
        """This run when transcription finished to tidy up UI."""
        self.progress_bar.setValue(100)
        self.transcribe_button.setEnabled(True)
        self.message_label.setText("")
        self.update_text_output()
    def set_progress_value(self, val):
        """Update progress bar value."""
        increment = int(math.floor(100*(float(val)/self.td)))
        self.progress_bar.setValue(increment)
    def process_and_transcribe_audio(self):
        """Process the audio into a textual transcription."""
        self.transcribe_button.setEnabled(False)
        self.message_label.setText("Converting mp4 to audio (*.wav)...")
        self.convert_mp4_to_wav()
    def update_text_output(self):
        """Update the text box with the transcribed file."""
        f = open(self.output_file, "r")
        self.transcribed_text.setText(f.read())
        f.close()
    def new_project(self):
        """Clear existing fields of data."""
        self.message_label.setText("")
        self.transcribed_text.setText("")
        self.selected_video_label.setText("")
        self.output_file_name.document().setPlainText("")
        self.progress_bar.setValue(0)
    def show_about(self):
        """Show about message box."""
        msg = QMessageBox()
        msg.setWindowTitle("About video to Speech")
        msg.setText("Nelson Petro - CSE 111")
        msg.setIcon(QMessageBox.Information)
        msg.exec_()

class convertVideoToAudioThread(QThread):
    """Thread to convert mp4 video file to wav file."""
    def __init__(self, mp4_file_name, audio_file):
        """Initialization function."""
        QThread.__init__(self)
        self.mp4_file_name = mp4_file_name
        self.audio_file = audio_file
    def __del__(self):
        """Destructor."""
        self.wait()
    def run(self):
        """Run video conversion task."""
        audio_clip = AudioFileClip(self.mp4_file_name)
        audio_clip.write_audiofile(self.audio_file)
        
class transcriptionThread(QThread):
    """Thread to transcribe file from audio to text."""
    change_value = pyqtSignal(int)
    def __init__(self, total_duration, audio_file, output_file):
        """Initialization function."""
        QThread.__init__(self)
        self.total_duration = total_duration
        self.audio_file = audio_file
        self.output_file = output_file
    def __del__(self):
        """Destructor."""
        self.wait()
    def run(self):
        """Run transcription, audio to text."""
        r = sr.Recognizer()
        for i in range(0, self.total_duration):
            try:
                with sr.AudioFile(self.audio_file) as source:
                    audio = r.record(source, offset=i*10, duration=10)
                    f = open(self.output_file, "a")
                    f.write(r.recognize_google(audio))
                    f.write(" ")
                self.change_value.emit(i)
            except:
                print("Unknown word detected...")
                continue
            f.close()
            
def main():
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())

if __name__ == "__main__":
    main()

并且我已经编写了这两个测试函数。 第一个测试MainWindow构造函数的默认值，第二个测试open_audio_file() function 的正确功能（使用上一个问题中提供的说明）。 我对 OOP 不是很熟悉，所以如果你能帮助我让第二个 function 正常工作，我将不胜感激。

这是两个测试函数：

def test_MainWindowConstructor():
  ui = Ui_MainWindow()
  assert ui.mp4_file_name == ""
  assert ui.output_file == ""
  assert ui.audio_file == "speech.wav"

def test_that_providing_a_raw_file_is_rejected():
  app = QtWidgets.QApplication(sys.argv)
  MainWindow = QtWidgets.QMainWindow()
  ui = Ui_MainWindow()
  ui.setupUi(MainWindow)
  ui.actionOpen_mp4_video_recording.triggered
  QFileDialog.getOpenFileName = "video.raw"  
  ui.open_audio_file
  assert ui.message_label.text == "Please select an *.mp4 file"

非常感谢你。

Answer 1

你写了：

  ui.actionOpen_mp4_video_recording.triggered
  ...  
  ui.open_audio_file

正如所写，这没有意义。 您可能想要调用 function，而不是评估表达式的副作用然后丢弃它。 fn和fn()之间有很大的区别——后者实际上调用了 function。

您正在成功验证triggered的属性是否存在，这对单元测试很有帮助。 要验证，请尝试一些拼写错误，例如“fliggered”，并注意引发的 AttributeError。

同样，您正在验证open_audio_file属性是否存在。 这是一个更简单的情况，因此单元测试这样做可能用处不大。 最好拨打 function，并验证其是否按预期运行。

---

尝试以这种方式运行测试：

$ pytest --cov --cov-report=term-missing

这将帮助您注意到您应该测试两种音频文件：带和不带“.mp4”后缀。

---

请注意，目标代码有时会提到 function 而没有调用它，也没有添加() 。 那里发生了什么事？ 我们将这种情况称为“ 回调”。 也就是说，目标代码的 API 接受一个指向 function 的指针（好的，一个引用）。它会记住 function，并随后在某些 UI 事件发生后的适当时间调用它。 该语法可能让您感到困惑——它解释了目标代码中缺少()的原因。

---

学术诚信

您显然正在学习这项作业中有关单元测试的一些知识，并且具有值得称赞的好奇心。 当你提交你的工作时，一定要包括对这个 SO 问题的引用。 只要您引用外部资源，大多数学校都乐于使用它们。