Question

我必须为这个类创建JUnit个测试用例。其中一个测试是测试ShannonsTheorem类的构造函数。有没有办法测试没有任何参数的构造函数？

另一个名为ShannonsModel的类也需要对其构造函数进行测试。根据我们提供的UML，在该构造函数上也没有参数。

谢谢！

package network;
import java.util.InputMismatchException;
import java.util.Scanner;

public class ShannonsTheorem {

    ShannonsModel model = new ShannonsModel();
    Scanner kb = new Scanner(System.in);

    /**
     * default constructor for ShannonsTheorem class.
     * 
     */
    public ShannonsTheorem()
    {

    }

    /**
     * Method to return the value in bandwidth variable.
     * @return
     */
    public double getBandwidth()
    {
        return model.getBandwidth();
    }

    /**
     * getSignalToNoise method to return the signalToNoise value in variable signalToNoise
     * @return
     */
    public double getSignalToNoise()
    {
        return model.getSignalToNoise();
    }

    /**
     * main method for ShannonsTheorem
     * @param args
     * while loop to handle user input to continue or end program
     */
    public static void main(String[] args) 
    {
        try {

            Scanner kb = new Scanner(System.in);

            Scanner scan = new Scanner(System.in);
            boolean stop = false;    
            while(!stop) { 

                ShannonsTheorem ST = new ShannonsTheorem();


                System.out.println("Enter bandwidth in hertz:");
                ST.setBandwidth(kb.nextDouble());
                System.out.println("Enter signalToNoise:");
                ST.setSignalToNoise(kb.nextDouble());

                System.out.println("Values are:");
                System.out.println("Bandwidth"); 
                System.out.println(ST.getBandwidth());
                System.out.println("SignalToNoise:"); 
                System.out.println(ST.getSignalToNoise());
                System.out.println(ST.maxiumumDataRate());


                System.out.println("Press any key to make another calculation.  Type N or n to Quit");
                String s = scan.nextLine();
                if(s.equals("n") || s.equals("N")) {
                    stop = true;
                } // end of if
            } // end of while loop

        }catch (InputMismatchException e){

            System.out.println("Input Exception was caught, restart program");

        }catch(NumberFormatException e){

            System.out.println("Format Exception was caught, restart program");

        }   
    }

    /**
     * public method to retrieve the maximum data rate. This method makes a call to the private method 
     * under the same name.
     * @return
     */
    public double maxiumumDataRate()
    {
        // calling to the private method maxiumumDataRate. Storing the return value from said method into variable result
        // when this public method is called it will return the result from the private method, 
        double result = model.maxiumumDataRate();
        System.out.print(model.toString());

        return result;
    }

    /**
     * setBandwidth method to set the bandwidth value in hertz
     * @param h
     */
    public void setBandwidth(double h)
    {
        model.setBandwidth(h);
    }

    /**
     * setSignalToNoise method to set the signalToNoise variable
     * @param snr
     */
    public void setSignalToNoise(double snr)
    {
        model.setSignalToNoise(snr);
    }
}

Answer 1

为什么需要测试构造函数？

您可以在不进行任何修改的情况下对其进行测试，默认构造函数具有一些特定字段：

@Test
public void shouldCreateADefaultShannonTheorem() {
    ShannonsTheorem shannonsTheorem = new ShannonsTheorem();

    Object expectedModel = new ShannonsModel();
    assertEquals(expectedModel , shannonsTheorem.model);
    Object expectedKb = new Scanner(System.in);
    assertEquals(expectedKb  , shannonsTheorem.kb);
}

或者您可以在没有任何更改的情况下测试它，默认构造函数会为您提供一些结果：

    ShannonsTheorem shannonsTheorem = new ShannonsTheorem();

    double expectedbandwith = 0.0;
    assertEquals(expectedbandwith , shannonsTheorem.getBandwidth(), 0);

    int expectedSignalToNoise = 0;
    assertEquals(expectedSignalToNoise  , shannonsTheorem.getSignalToNoise(), 0);

    int expectedMaximumDataRate = 0;
    assertEquals(expectedMaximumDataRate , shannonsTheorem.maxiumumDataRate(), 0);


    // ...

这就是为什么它有用来做TDD（先测试）：

您的应用应该做什么？写测试。 //这是思考
编写代码。 //不要在这里思考！
重构

Junit - 测试没有参数的构造函数？

1 个答案: