Powermockito给我一个空异常

Question

我试图模拟一些静态方法，但得到以下堆栈跟踪

java.lang.NullPointerException
at de.unibonn.iai.eis.luzzu.semantics.utilities.SPARQLHelper.toSPARQL(SPARQLHelper.java:12)
at de.unibonn.iai.eis.luzzu.semantics.utilities.DAQHelper.getDomainResource(DAQHelper.java:51)
at de.unibonn.iai.eis.luzzu.semantics.utilities.DAQHelper.getCategoryResource(DAQHelper.java:47)
at de.unibonn.iai.eis.luzzu.annotations.QualityMetadataTest.createMockedMetric(QualityMetadataTest.java:211)
at de.unibonn.iai.eis.luzzu.annotations.QualityMetadataTest.<init>(QualityMetadataTest.java:81)
....

DAQHelper是一个静态类，它是从我当前正在测试的方法调用的。为了保持故事简短，我有一个方法addMetricData（…）调用getCategoryResource（…）等此getCategoryResource（…）是一个公共静态方法，它反过来调用getDomainResource（DAQHelper中的私有静态方法）。getDomainResource（…）方法调用静态SPARQLHelper。toSPARQL（…）方法

你知道我为什么会有这个问题吗？测试代码如下：

@RunWith(Parameterized.class)

@PrepareForTest（{DAQHelper.class，SPARQLHelper.class}）公共类QualityMetadataTest扩展了断言{

@Rule
public PowerMockRule rule = new PowerMockRule();

private QualityMetric metric;
private Model m = ModelFactory.createDefaultModel();
private QualityMetadata _testClass;
private Dataset _dataset;

private Resource metricResource = m.createResource("example:mockedMetric");
private Resource categoryResource = m.createResource("example:mockedCategory");
private Resource dimensionResource = m.createResource("example:mockedDimension");
private Resource dimensionProperty = m.createResource("example:hasMockedDimensionProperty");
private Resource metricProperty = m.createResource("example:hasMockedMetricProperty");
private Resource computedOn = m.createResource("example:testing");
private Resource qualityGraphURI;

private Resource categoryURI;
private Resource dimensionURI;
private Resource metricURI;

private boolean parameter;

@Parameters
public static Collection<Object[]> data() {
    Object[][] data = new Object[][] { { false } };
    return Arrays.asList(data);
}

public QualityMetadataTest(boolean QualityMetadataExists) throws Exception{
    this.parameter = QualityMetadataExists;
    if (QualityMetadataExists){
        // fill model m with quality metadata
    }

    this.createMockedMetric();

    _testClass = new QualityMetadata(m,computedOn);
    _testClass.addMetricData(metric);
    _dataset = _testClass.createQualityMetadata();
} 
// some test methods
    private void createMockedMetric() throws Exception{     
    metric = mock(QualityMetric.class);
    when(metric.getMetricURI()).thenReturn(metricResource);
    when(metric.metricValue()).thenReturn(0.5);


    mockStatic(DAQHelper.class);    
    PowerMockito.when(DAQHelper.getCategoryResource(metricResource)).thenReturn(categoryResource);
    PowerMockito.when(DAQHelper.getDimensionResource(metricResource)).thenReturn(dimensionResource);
    PowerMockito.when(DAQHelper.getPropertyResource(dimensionResource)).thenReturn(dimensionProperty);
    PowerMockito.when(DAQHelper.getPropertyResource(metricResource)).thenReturn(metricProperty);
}

我的信念是，一旦“当”方法被创建，它们就会被全局创建，并且不会真正执行该方法，而只是返回结果。我可能有一个误解。你有什么想法吗？

干杯

Answer 1

在javadoc中：<代码>所有用法都需要在类级别上注释@RunWith（PowerMockRunner.class）和@PrepareForTest 因此，看起来您不能将PrepareForTest与参数化的代码一起使用