参数化JUnit测试中使用数组参数的反射异常

Question

我试图在JUnit 4.11中设置参数化测试，该参数化测试生成单个参数。然而，这个参数需要是一个数组本身。

为下面的代码段的预期的行为将是test()运行两次而arguments保持在第一次运行的阵列{"test1", "test2"}和在第二次运行的阵列{"test3", "test4"}。

@RunWith(Parameterized.class) 
public class Tester { 

    @Parameter 
    private String[] arguments; 

    @Parameters 
    public static Iterable<Object[]> data() { 
     return Arrays.asList(
       new Object[][]{ 
        {new String[] {"test1","test2"}}, 
        {new String[] {"test3","test4"}} 
       } 
     ); 
    } 

    @Test 
    public void test() { 
     fail(); 
    } 
} 

但是，当我执行测试时，抛出了一个SlowCheckMemberAccess异常。 Google没有提供这种问题的结果。

任何人都可以解释这里出了什么问题吗？

未过滤的JUnit的轨迹是：

java.lang.IllegalAccessException: Class org.junit.runners.Parameterized$TestClassRunnerForParameters can not access a member of class org.mafagafogigante.dungeon.entity.creatures.Tester with modifiers "private" 
at sun.reflect.Reflection.ensureMemberAccess(Unknown Source) 
at java.lang.reflect.AccessibleObject.slowCheckMemberAccess(Unknown Source) 
at java.lang.reflect.AccessibleObject.checkAccess(Unknown Source) 
at java.lang.reflect.Field.set(Unknown Source) 
at org.junit.runners.Parameterized$TestClassRunnerForParameters.createTestUsingFieldInjection(Parameterized.java:201) 
at org.junit.runners.Parameterized$TestClassRunnerForParameters.createTest(Parameterized.java:179) 
at org.junit.runners.BlockJUnit4ClassRunner$1.runReflectiveCall(BlockJUnit4ClassRunner.java:244) 
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) 
at org.junit.runners.BlockJUnit4ClassRunner.methodBlock(BlockJUnit4ClassRunner.java:241) 
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70) 
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50) 
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238) 
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63) 
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236) 
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53) 
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229) 
at org.junit.runners.ParentRunner.run(ParentRunner.java:309) 
at org.junit.runners.Suite.runChild(Suite.java:127) 
at org.junit.runners.Suite.runChild(Suite.java:26) 
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238) 
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63) 
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236) 
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53) 
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229) 
at org.junit.runners.ParentRunner.run(ParentRunner.java:309) 
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86) 
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) 
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459) 
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678) 
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382) 
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192) 

Answer 1

注释@Parameter的字段必须是public。

JUnit 4.13 will have an improved error message：

Cannot set parameter 'arguments'. Ensure that the field 'arguments' is public. 

Answer 2

我不认为你需要Arrays.asList()作为数组Iterable，太。

如果您为其指定单个数组参数，那么Arrays.asList()也可能被愚弄。如果你想使用它，添加显式强制转换。