當我運行我的測試用例時，我的 spring-boot 的主要方法被喚起並且我的 mockito 方法不起作用。 如何解決這個問題？

Question

我編寫了一個測試用例，它模擬應用程序從系統讀取 excel 文件的方法調用。 當我在調試中運行我的測試用例時，我觀察到我的控件通過我的 spring-boot 應用程序的 main 方法，而不是在我的服務方法中獲取模擬值，我只得到 null。 結果，我在下一行收到了一個空指針異常。

我不確定如何在測試模式下正確運行應用程序，在這種模式下我可以成功模擬我正在嘗試的方法調用。

測試方法：

@Test
    public void testReadQuery() throws IOException {
        QueryReader mockQueryReader = Mockito.mock(QueryReader.class);
        Mockito.when(fileReaderWriter.readFile())
          .thenReturn(mockDataRetriever.getResponseObject(new File(getClass().getResource(TestConstants.TEST_QUERY).getFile())));
        Object mockTableObj = ReflectionTestUtils.getField(mockQueryReader, "tableObj");
        ReflectionTestUtils.invokeMethod(mockQueryReader, "readQuery");
        assertNotNull(mockTableObj);
    }

主要方法類：

public static void main(String[] args) {
        SpringApplication.run(QueryBuilderApplication.class, args);
    }

    @Override
    public void run(String... args) throws Exception {

        queryReader.readQuery();

        exit(0);
    }

服務方式：

public void readQuery() {

        try {

            XSSFWorkbook workbook = fileReaderWriter.readFile();
            XSSFSheet sheet = workbook.getSheetAt(0);
            String sheetName = sheet.getSheetName();

java.lang.NullPointerException
    at com.QueryBuilder.reader.QueryReader.readQuery(QueryReader.java:31)
    at com.QueryBuilder.QueryBuilderApplication.run(QueryBuilderApplication.java:25)
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:813)
    at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:797)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:324)
    at org.springframework.boot.test.context.SpringBootContextLoader.loadContext(SpringBootContextLoader.java:127)
    at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:99)
    at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:117)
    at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:108)
    at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:118)
    at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:83)
    at org.springframework.boot.test.autoconfigure.SpringBootDependencyInjectionTestExecutionListener.prepareTestInstance(SpringBootDependencyInjectionTestExecutionListener.java:44)
    at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:246)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:227)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:289)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:291)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:246)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:89)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:41)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:541)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:763)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:463)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:209)

Answer 1

發生這種情況可能是因為您沒有存根要測試的類中的所有對象。 對於默認值，Mockito 返回模擬對象的存根方法的默認值，例如 Null 表示對象，false 表示布爾值。

為了驗證我的意見，您可以使用以下語句來創建模擬實例

Mockito.mock(ClassToTest.class, Mockito.RETURNS_DEEP_STUBS); 

它會返回一個深存根。 例如：

@Test
public void when_returns_deep_stub() throws Exception {
    ClassToTest classToTestWithDeepStub = Mockito.mock(ClassToTest.class, Mockito.RETURNS_DEEP_STUBS);
    // the object1 and object2 mock is not defined
    // deep call of getString method
    when(classToTestWithDeepStub.getObject1().getObject2().getString())
    .thenReturn("Deep Stub");
    // a deep stubbed mock is returned
    System.out.println("classToTestWithDeepStub.getObject1().getObject2().getString()"
    + classToTestWithDeepStub.getObject1().getObject2().getString());
    assertNotNull(classToTestWithDeepStub.getObject1().getObject2().getString());
}

控制台輸出

 classToTestWithDeepStub.getObject1().getObject2().getString()=Deep Stub.

---

第二種解決方案

從您的問題中，我了解到 fileReaderWriter 為空，對嗎？ 如果這是真的，我在 QueryReader 類中看不到 fileReaderWrite 的模擬和模擬注入。 你能給我更多關於你的實現的細節或陳述嗎？ 否則我的建議是遵循以下方式。

@RunWith(MockitoJUnitRunner.class)
public class ReadQueryTest {

  @Mock
  private FileReaderWriter fileReaderWriter;

  @Test
  public void testReadQuery() throws IOException { 
     QueryReader queryReader = new QueryReader(fileReaderWriter);
     when(fileReaderWriter.readFile())
          .thenReturn(mockDataRetriever.getResponseObject(new File(getClass().getResource(TestConstants.TEST_QUERY).getFile())));
     queryReader.readQuery();
     assertNotNull(queryReader.getTableObj());
  }
}