java – 参数化jUnit测试中的继承(或替代)

2019年7月20日 178次阅读

我想在jUnit中做这样的事情：

@Runwith(Parameterized.class)
public abstract class BaseTest {

     protected abstract List<Object[]> extraParams();
     protected abstract ClassUnderTest testObject;

     @Parameters
     public Collection<Object[]> data() {
         List<Object> params = ...; // a standard set of tests
         params.addAll(extraParams());
         return params;
     }

     @Test
     public doTest() {
         // assert things about testObject
     }
}

public class ConcreteTest extends BaseTest {
     protected ClassUnderTest = new ConcreteClass(...);
     protected List<Object[]) extraParams() {
         List<Object> extraParams = ...; // tests specific to this concrete type
         return extraParams;
     }
}

因此,通过扩展这个类,我针对被测对象运行了一系列标准测试,并在具体类中指定了一些额外的测试.

但是,jUnit要求@Parameters方法是静态的.我还能如何在整体课程中有一套标准参数加上额外的参数来实现目标？

到目前为止,我提出的最好的方法是使用未注释的集合< Object []> abstractParams()在抽象类中,并要求子类包含一个方法：

 @Parameters
 public Collection<Object[]> data() {
     List<Object> params = standardParams();
     params.addAll(...); // extra params
     return params;
 }

……但这并不像我想的那样整洁,因为它对子类的作者负有太多责任.

最佳答案 JUnit期望@Parameters方法必须是静态的,如果不提供静态方法,它会在类Exception上抛出No public static parameters方法.

但是你可以通过实现org.junit.rules.TestRule来实现你的要求,如下所示：

BaseTest class

public abstract class BaseTest {

    @Rule
    public MyBaseTestRule myProjectTestRule = new MyBaseTestRule(data());

    protected abstract List<Object[]> extraParams();

    public List<Object[]> data() {  
        List<Object[]> listTotal = new ArrayList<>();
        listTotal.addAll(extraParams());
        //add your base test data here
        return listTotal;
    }

    public abstract List<Object[]> extraParams();
}

ConcreteTest class

public class ConcreteTest extends BaseTest  {

    @Override
    public List<Object[]> extraParams() {
        List<Object[]> list = ...//set up data here
        return list;
    }   

    @Test
    public void test1() {
        Object[] testData = myProjectTestRule.getTestData();
        //use the test data for the test
        //Example: Assume addition of two integers scenario and data 
        //data[0] expectedresult, data[1],[2] inputs
        //Assert.assertEquals((int)data[0], (int)(data[1]+data[2]));

    }

    //add other test cases
}

MyBaseTestRule class:

import java.util.List;

import org.junit.rules.TestRule;
import org.junit.runner.Description;
import org.junit.runners.model.Statement;

public class MyBaseTestRule implements TestRule { 

    private final List<Object[]> totalTestData;

    private final int totalTestsSize;

    private int currentTestIndex;

    public MyProjectTestRule(List<Object[]> list) {
      this.totalTestsSize = list.size();
      this.totalTestData = list;
   }

   public Object[] getTestData(){
      return totalTestData.get(currentTestIndex);
   }

   @Override
   public Statement apply(Statement stmt, Description desc) {

      return new Statement() {

         @Override
         public void evaluate() throws Throwable {
            for(int i=0; i<totalTestsSize; i++) {
                currentTestIndex = i;
                stmt.evaluate();
            }
         }
       };
    }
}
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