Question

我正在学习JUnit测试，并且我已经获得了使用参数进行测试的示例，因此我正在应用此文档以及Daniel Mayer's Our Craft和Mkyong等网站的文档和示例。

我被要求用参数化类测试fill（）方法。这是原始课程：

package FuelTankTestPractice;

/**
 * FuelTank is the class which represents the fuel tank of a car.
 * A FuelTank object encapsulates the state information needed for describing the state of the tank:
 * <ul>
 *   <li> tankMax   capacity of the tank
 *   <li> tankLevel fuel level of the tank
 * </ul>
 * 
 * class invariant      0.0 &lt;= tankLevel &lt;= tankMax
 * 
 * @author UC3M MOOC Team
 *
 */
public class FuelTank {

    private double tankMax;
    private double tankLevel;

   /**
    * FuelTank is a constructor of the class. 
    * 
    * <hr>
    * <br> precondition  tankMax &gt; 0.0 and 0.0 &lt;= tankLevel &lt;= getTankMax()  
    * <br> postcondition tankMax &gt; 0.0 and 0.0 &lt;= tankLevel &lt;= getTankMax() 
    * <hr>
    * 
    * @param tankMax  is the amount of fuel  (measured in liters) that the tank can hold
    * @param tankLevel is the amount of fuel (measured in liters) that the tank will have initially
    * 
    */ 
    FuelTank(double tankMax, double tankLevel) {
       this.tankMax   = tankMax;
       this.tankLevel = tankLevel;
    }

   /**
    * getTankLevel is an accessor method
    * 
    * @return   the amount of fuel in the tank
    */
    public double getTankLevel(){
       return tankLevel;
    }

   /**
    * getTankMax is an accessor method
    * 
    * @return   the capacity (in liters) of the tank
    */
    public double getTankMax(){
       return tankMax;
    }

   /**
    * isEmpty gives a status report 
    * 
    * @return   <code>true</code> if the tank is empty 
    *          <code>false</code> otherwise.
    */
    public boolean isEmpty(){
      return tankLevel == 0;
    }

    /**
     * isFull gives a status report 
     * 
     * @return  <code>true</code> if the tank is full 
     *          <code>false</code> otherwise.
     */
    public boolean isFull(){
      return tankLevel == tankMax;
    }

   /**
    * fill is a mutator method that adds fuel to the tank
    * 
    * <hr>
    * <br> precondition     0.0 &lt; amount &lt;= getTankMax() - getTankLevel() 
    * <br> postcondition    not empty
    * <br> postcondition    tankLevel &gt; tankLevel_initial 
    * <hr>
    * 
    * @param amount     the quantity of fuel to add
    * 
    */
    public void fill(double amount){
       tankLevel = tankLevel + amount;
    }

   /**
    * consume is a mutator that consumes amount of fuel
    * 
    * @param amount the amount of fuel to consume
    * 
    */
    public void consume(double amount){
       tankLevel = tankLevel - amount;
    }
}

首先，我必须创建一个简单的测试类，它没有问题：

package FuelTankTestPractice;

/**
 * Tests for class FuelTank.
 * 
 * All tests in the folder "test" are executed 
 * when the "Test" action is invoked.
 * 
 */

import static org.junit.Assert.*;
import org.junit.Test;
import org.junit.Before;

public class FuelTankTest {

    FuelTank tank = null;

    @Before
    public void setUp() throws Exception {
    tank = new FuelTank(60.0,10.0);
    }

    @Test
    public void testGetTankLevel() {
    tank.getTankLevel();
    assertTrue(tank.getTankLevel()==0.0);
    }

    @Test
    public void testGetTankMax() {
    tank.getTankMax();
    assertTrue(tank.getTankMax()==60.0);
    }

    @Test
    public void testIsEmpty() {
    tank.isEmpty();
    assertTrue(!tank.isEmpty());
    }

    @Test
    public void testHalfFullTank() {
    assertTrue(tank.getTankMax()/2==30.0);
    }

 }

但现在这是我带参数的测试类（想法是测试fill（）方法：

package FuelTankTestPractice;

import static org.junit.Assert.assertTrue;
import java.util.Arrays;
import java.util.Collection;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;

@RunWith(Parameterized.class)
public class FillingTest extends FuelTankTest{
private double amount;
private double result;

//constructor
public FillingTest (double amount, double result) {
this.amount = amount;
this.result = result;
}

FuelTank tank = new FuelTank(60, 10);

//Declares parameters here
public static Collection<Object[]> fillAmounts(){ 
    Object[][] amounts = new Object[][]{
        {10.0,20.0},
        {15.0,35.0},
        {20.0,30.0},
        {35.0,45.0}}; 
return Arrays.asList(amounts); 
}

@Test   
public void TestFill() {
tank.fill(amount);
assertTrue(amount + tank.getTankLevel() == result);
    }
}

主要的类和方法非常简单，但如果它有帮助我会添加它：

public class Main {

public static void main(String[] args) {

    // create the tank
    FuelTank tank = new FuelTank(40.0,0.0);

    System.out.print("The tank with capacity " + tank.getTankMax() + " liters has been created. ");
    System.out.println(" Its initial fuel level is  " + tank.getTankLevel() + " liters.");
}
}

我做了很多修改以适应示例，但是大多数都不考虑另一个测试类（我需要按照指示最终创建一个JUnit测试套件）。有时它会抛出：

java.lang.Exception: No public static parameters method on class FuelTankTestPractice.FillingTest
    at org.junit.runners.Parameterized.getParametersMethod(Parameterized.java:299)
    at org.junit.runners.Parameterized.<init>(Parameterized.java:246)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
    at org.junit.internal.builders.AnnotatedBuilder.buildRunner(AnnotatedBuilder.java:104)
    at org.junit.internal.builders.AnnotatedBuilder.runnerForClass(AnnotatedBuilder.java:86)
    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
    at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:26)
    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
    at org.junit.internal.requests.ClassRequest.getRunner(ClassRequest.java:33)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.createUnfilteredTest(JUnit4TestLoader.java:84)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.createTest(JUnit4TestLoader.java:70)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.loadTests(JUnit4TestLoader.java:43)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:444)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)

我希望所有这些信息都有帮助。它不是要解决我的“家庭作业”，而是要解决学习问题。在考虑作为一个菜鸟问题之前，请求我任何你需要的东西，我已经完成了所有的研究，但我相信例子不符合我的问题，或者我可能不知道应该看到差异。

Answer 1

您声明您的测试类应该用作@RunWith(Parameterized.class)

这意味着它提供了一个带有@Parameters注释的方法。

因此：将此注释添加到方法fillAmounts()中，您应该很好。

错误信息基本上告诉您，跑步者无法找到完成工作所需的方法。

Answer 2

这是通过测试的最终工作代码：

package FuelTankTestPractice;

import static org.junit.Assert.assertEquals;
import java.util.Arrays;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;
import org.junit.runners.Parameterized.Parameters;

//Part 1: Runwith
@RunWith(Parameterized.class)
public class FillingTest {

    private double amount;
    private double result;

    //Part 2: Constructor
    public FillingTest (double amount, double result) {
        this.amount = amount;
        this.result = result;
    }

    //Part 3: Declares parameters here
    @Parameters
    public static Collection<Object[]> fillAmounts(){ 
        Object[][] amounts = new Object[][]{
            {10.0,20.0},
            {15.0,25.0},
            {20.0,30.0},
            {35.0,45.0}}; 
        return Arrays.asList(amounts);
    }

    // Part 4: Test method
    FuelTank tank = new FuelTank(60.0,10.0);    

    @Test
    public void TestFill() {
        tank.fill(amount);
        assertEquals(result, tank.getTankLevel(), 0.0001); 
        // Or assertTrue(tank.getTankLevel() == result);
    }
}

与问题代码相比，第3部分缺少@Parameters行。此外，第4部分中的assertTrue（）行是错误的，因为tank.fill(amount);已添加＆＃34;金额＆＃34;坦克级别。

为了本课程的目的，我使用了assertEquals而不是assertTrue（我让我寻找＆＃34; delta＆＃34;的意思）。

在带参数的测试中找不到JUnit测试

2 个答案: