### Question:
JsonImportDownloadReader implements ItemStreamReader<JsonJudgmentItem> { @Override public void open(ExecutionContext executionContext) throws ItemStreamException { importFiles = Lists.newLinkedList(importFileUtils.listImportFiles(importDir)); currentFile = importFiles.poll(); fileReader = null; jsonParser = null; }  @Override JsonJudgmentItem read(); @Override void open(ExecutionContext executionContext); @Override void update(ExecutionContext executionContext); @Override void close(); void setImportDir(String importDir); @Autowired void setImportFileUtils(ImportFileUtils importFileUtils); @Autowired void setJsonFormatter(JsonFormatter jsonFormatter); @Autowired void setJsonFactory(JsonFactory jsonFactory);  }### Answer:
@Test public void open() { File importFile1 = new File("f1.json"); File importFile2 = new File("f2.json"); File importFile3 = new File("f3.json"); List<File> importFiles = Lists.newArrayList(importFile1, importFile2, importFile3); when(importFileUtils.listImportFiles(importDir)).thenReturn(importFiles); ExecutionContext ctx = Mockito.mock(ExecutionContext.class); jsonImportDownloadReader.open(ctx); Mockito.verifyZeroInteractions(ctx); assertDownloadReaderState(importFile1, null, null, importFile2, importFile3); }