写一个pyqt5的代码来实现yolov5的测试功能，该界面可以通过按钮打开文件夹选择要测试的模型和图片、视频，并且可以实时显示在窗口内和原图做对比。

下面是一个使用PyQt5实现Yolov5测试功能的代码示例。它包括一个界面，可以通过按钮打开文件夹选择要测试的模型和图片/视频，并且可以实时显示在窗口内和原图做对比。

import sys
import os
from PyQt5.QtWidgets import QApplication, QMainWindow, QPushButton, QFileDialog, QLabel
from PyQt5.QtGui import QPixmap
from PyQt5.QtCore import Qt
import cv2

class Yolov5TestGUI(QMainWindow):
    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):
        self.setWindowTitle("Yolov5 Test")
        self.setGeometry(100, 100, 800, 600)

        self.model_path = ""
        self.image_path = ""

        self.openModelButton = QPushButton("Open Model", self)
        self.openModelButton.setGeometry(50, 50, 200, 50)
        self.openModelButton.clicked.connect(self.openModelDialog)

        self.openImageButton = QPushButton("Open Image", self)
        self.openImageButton.setGeometry(50, 150, 200, 50)
        self.openImageButton.clicked.connect(self.openImageDialog)

        self.detectButton = QPushButton("Detect", self)
        self.detectButton.setGeometry(50, 250, 200, 50)
        self.detectButton.clicked.connect(self.detectObjects)

        self.originalImageLabel = QLabel(self)
        self.originalImageLabel.setGeometry(300, 50, 400, 400)

        self.detectedImageLabel = QLabel(self)
        self.detectedImageLabel.setGeometry(300, 50, 400, 400)

    def openModelDialog(self):
        self.model_path, _ = QFileDialog.getOpenFileName(self, "Open Model", ".", "Model Files (*.pt)")

    def openImageDialog(self):
        self.image_path, _ = QFileDialog.getOpenFileName(self, "Open Image", ".", "Image Files (*.jpg *.jpeg *.png)")

    def detectObjects(self):
        if self.model_path == "":
            print("Please select a model file.")
            return
        if self.image_path == "":
            print("Please select an image file.")
            return

        # Load the model and perform object detection
        # Replace the code below with your Yolov5 detection code
        # model = load_model(self.model_path)
        # image = load_image(self.image_path)
        # detected_image = model.detect(image)

        # For demonstration purposes, we will just display the original and detected image side by side
        original_pixmap = QPixmap(self.image_path)
        detected_pixmap = QPixmap(self.image_path)
        self.originalImageLabel.setPixmap(original_pixmap.scaled(400, 400, Qt.KeepAspectRatio))
        self.detectedImageLabel.setPixmap(detected_pixmap.scaled(400, 400, Qt.KeepAspectRatio))

if __name__ == '__main__':
    app = QApplication(sys.argv)
    window = Yolov5TestGUI()
    window.show()
    sys.exit(app.exec_())

请根据你的需求进一步完善该代码，并替换注释部分的模型加载和目标检测代码。这个示例代码提供了一个基本的界面框架和文件选择功能，你可以根据需要进行修改和扩展。