java - 使用数组参数的参数化 JUnit 测试中的反射异常

Question

我尝试在 JUnit 4.11 中设置一个参数化测试，它生成一个单个参数。但是，此参数本身必须是一个数组。

以下代码片段的预期行为是 test() 运行两次，而 arguments 包含一个数组 {"test1", "test2"} 在第一次运行中，数组 {"test3", "test4"} 在第二次运行中。

@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。谷歌没有为这类问题提供任何结果。

谁能解释这里出了什么问题？

未经过滤的 JUnit 跟踪是:

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

用@Parameter注解的字段必须是public。

JUnit 4.13 will have an improved error message :

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